The role of catabolism. What is catabolism? Catabolism processes, stages

Greetings to all lovers of a healthy lifestyle and sports!

Today we will talk again about a complex, but very interesting topic - metabolic processes. In the previous article, we met ourselves. And what does the process of metabolism or metabolism include. The metabolic process includes catabolism and anabolism.

One process is called destructive-it catabolism, from the Greek καταβολή, "dropping, destruction". In the body, when food is received, the process of splitting complex substances into simpler ones takes place. During this process, decay (dissimilation), including obsolete tissue and cellular elements, occurs, after which they are removed from the body with water. There are 3 stages of catabolism:

• Stage I preparatory (proteins are broken down into amino acids; fats into glycerol and fatty acids; starch into glucose).
• Stage II is called glycolysis or anoxic. Enzymes are involved in it; glucose is broken down. 60% of the energy is dissipated as heat, and 40% is used for fusion. Oxygen is not involved in this.
• Stage III cellular oxygen respiration. Enzymes and oxygen are involved in it. Lactic acid is broken down. CO2 is released from mitochondria into the environment.

For example, they used a cutlet and milk, the proteins containing them are different in structure and cannot replace each other, therefore, with the help of special enzymes, protein from milk and cutlets are disassembled into amino acids, which are then used. In addition, in the process of catabolism, fat is burned, which is so hated by fat people. In parallel, energy is released, measured in calories. The catabolic process in power sports is viewed negatively. Catabolism is necessary for emergency replenishment by the body of the substances it needs. With regard to bodybuilding, catabolic processes lead to muscle breakdown, that is, protein (muscle) tissue is broken down to the level of digestible amino acids. It turns out the body eats itself.

Other process creative- it anabolism from the Greek ἀναβολή, "rise" or plastic metabolism - a set of chemical processes that make up one of the sides of metabolism in the body, aimed at the formation of cells and tissues. For example, protein synthesis in the body, i.e. formation of proteins from simple amino acids. As a result of plastic metabolism, proteins, fats, carbohydrates characteristic of the body are built from the nutrients entering the cell, which, in turn, go to the creation of new cells, their organs, and intercellular substance. Unlike catabolism, this process is the best companion for bodybuilders, as new muscle tissue is built, including from fat deposits, hence muscle growth. For an active set of muscle tissue, it is necessary to increase the level of anabolism, with the help of testosterone and insulin, and at the same time reduce the level of catabolism, reduce the level of cortisol, adrenaline and glycogen.

Several factors influence the rate of metabolic reactions in the body.:

• Gender - in men, the rate of metabolic processes is 20% higher than in women
• Age - the metabolic process every 10 years decreases by 3% from the level of 25-30 years
• Body weight - if fat in its mass exceeds the total mass of internal organs, bones and of course muscles, then the rate of the catabolic process is lower.
• Physical activity - regular exercise increases the metabolic rate, the first 2-3 hours after training by 20-30%, then no more than 2-7%.
• Heredity - You can inherit your metabolic rate from previous generations.
• Thyroid dysfunctions are hypothyroidism (low levels of thyroid hormones) and hyperthyroidism (increased hormonal activity of the thyroid gland). These conditions can slow or speed up the metabolism, but only 3% of the population has hypothyroidism and 0.3% has hyperthyroidism.

What could be the reasons for slowing down metabolism and not contributing to weight loss or weight gain.

• Reducing calories. If you decide to lose weight and cut calories, then keep in mind that malnutrition can harm your metabolism. The body tries to conserve reserves and inhibits metabolism. Therefore, if there are not enough calories in the body, then the body will take them from muscle tissue as energy. Therefore, eat more often, but in small portions.
• Lack of fiber. The absence or small amount of such wonderful foods as whole grain bread, durum wheat spaghetti and vegetables in the diet negatively affects the quality of metabolism. Daily intake of fiber (about 100 g) can reduce weight by 5-7% over time, depending on the person's weight.
• Lack of proteins. Protein, as we know, is the building block of muscles. With the active consumption of proteins, you can burn fat and not many people know this. Indeed, if your diet is sufficiently completed with proteins (meat, fish, poultry, nuts, mushrooms, dairy products), then it is quite possible to get rid of 20-25% of calories, because. proteins activate metabolism.
• No caffeine. To maintain metabolism at a certain level, it is necessary to consume products containing caffeine from time to time (if there are no contraindications). It doesn't have to be coffee. Green tea is also a great source of caffeine. For example, green tea can improve metabolism by 15%. Due to its properties, tea, as it were, gives an impetus to the body to burn calories.
• Lack of calcium. Systematically consume foods containing calcium (cheese, cottage cheese, milk). By the way, calcium is very important for women.
• Water temperature. A very interesting fact is that cold water speeds up metabolism. This is due to the fact that the body spends energy to heat the water. Water, in principle, should be drunk in abundance (2 - 2.5 liters per day), and cool water improves metabolic processes.
• Lack of vitamin D. Vitamin D is directly involved in metabolism. How many people (especially the elderly) do you know who support their intake of oily fish (trout, salmon, mackerel), bran, eggs? After all, these foods are the best natural sources of vitamin D.
• Lack of iron. Iron is paramount for burning fat. First of all, this iron is associated with the delivery of oxygen to the muscles, in which part of the fat is burned. Either special iron supplements or natural sources (seafood, meat, oatmeal, greens) will help you replenish iron, and therefore improve metabolism.
• Lack of omega-3 and omega-6 fatty acids in the diet by eating at least 2-3 servings of fish per week. If you don't like fish, get the above acids from dietary supplements. The simplest solution is to take fish oil.
• Presence of alcohol. Did you know that if there is alcohol in the blood, the body will burn it first, and only then the rest of the calories. By reducing your alcohol intake, you will help your body burn the exact calories you don't need. In any case, reducing the dose of alcohol will only benefit you.
• Not enough time for sleep. Sleep deprivation has many side effects, and nodding off on the bus on your way to work is just one of them. Researchers have found a direct link between metabolism and sleep; Sleep deprivation has been proven to seriously slow down your metabolism.
• Don't eat breakfast in the morning. If in the morning your body has not received an energy boost, then for lunch and dinner you will want something high-calorie. If you don't want to eat in the morning, have a light snack like yogurt.
• Do not use spices when cooking. The next time you cook chicken or meat, add a pinch of cayenne pepper. It owes its hotness to capsaicin, which not only adds spice to the dish, but also helps speed up the metabolism. This conclusion was reached by H. S. Reinbach, A. Smits, T. Martinussen from the University of Copenhagen in their study "The effect of capsaicin, green tea and sweet pepper on appetite and energy expenditure in people with negative and positive energy balance."
• Lead an inactive lifestyle. Increase activity. The less you move, the slower your metabolism. Do short, intense exercise, which can speed up your metabolism and cause your body to burn calories even after the exercise is over. For example, take a bike ride, studies show that 45 minutes of riding a two-wheeled friend speeds up the metabolism for the next 12 hours or more.
• Smile a little, yes, yes!!! Don't let it sound pseudo-scientific to you, scientists have confirmed that at least 10 minutes of laughter a day can help you burn calories.

By adhering to these simple rules, you can achieve excellent results for any person, there would be only a goal and desire. In the following, we will talk about male and

Table of contents of the subject "Metabolism and Energy. Nutrition. Basic Metabolism.":

2. Proteins and their role in the body. Wear coefficient according to Rubner. Positive nitrogen balance. Negative nitrogen balance.
3. Lipids and their role in the body. Fats. Cellular lipids. Phospholipids. Cholesterol.
4. Brown fat. Brown adipose tissue. Blood plasma lipids. Lipoproteins. LDL. HDL. VLDL.
5. Carbohydrates and their role in the body. Glucose. Glycogen.


8. The role of metabolism in providing the energy needs of the body. Phosphorylation coefficient. Caloric equivalent of oxygen.
9. Methods for assessing the energy costs of the body. Direct calorimetry. Indirect calorimetry.
10. Basic exchange. Equations for calculating the value of the main exchange. Body surface law.

Metabolism and energy lies at the basis of all manifestations of life activity and is a set of processes of transformation of substances and energy in a living organism and the exchange of substances and energy between the organism and the environment.

To keep alive during metabolism and energy the plastic and energy needs of the body are provided. Plastic needs are met at the expense of substances used to build biological structures, and energy needs are met by converting the chemical energy of nutrients entering the body into the energy of high-energy (ATP and other molecules) and reduced (NADP H - nicotine amide adenine dinucleotide phosphate) compounds. Their energy is used by the body to synthesize proteins, nucleic acids, lipids, as well as components of cell membranes and cell organelles, to perform cell activities associated with the use of chemical, electrical and mechanical energy.

Metabolism and energy (metabolism) in the human body - a set of interrelated, but multidirectional processes: anabolism (assimilation) and catabolism (dissimilation).

Anabolism- this is a set of processes of biosynthesis of organic substances, cell components and other structures of organs and tissues. Anabolism ensures the growth, development, renewal of biological structures, as well as the continuous resynthesis of macroergic compounds and their accumulation.

catabolism- this is a set of processes for the breakdown of complex molecules, components of cells, organs and tissues to simple substances (using some of them as biosynthesis precursors) and to the final products of metabolism (with the formation of macroergic and reduced compounds).

The relationship between the processes of catabolism and anabolism It is based on the unity of biochemical transformations that provide energy for all vital processes and the constant renewal of body tissues. The conjugation of anabolic and catabolic processes in the body can be carried out by various substances, but the main role in this conjugation is played by ATP, NADP H. Unlike other mediators of metabolic transformations, ATP is cyclically rephosphorylated, and NADP H is restored, which ensures the continuity of the processes of catabolism and anabolism.

Providing energy for life processes is carried out due to anaerobic (oxygen-free) and aerobic (using oxygen) catabolism proteins, fats and carbohydrates that enter the body with food. During the anaerobic breakdown of glucose (glycolysis) or its reserve substrate glycogen (glycogenolysis), the conversion of 1 mole of glucose into 2 moles of lactate results in the formation of 2 moles of ATP. Lactate is an intermediate product of metabolism. In the chemical bonds of its molecules, a significant amount of energy has been accumulated. The energy generated during anaerobic metabolism is not enough to carry out the vital processes of animal organisms. Due to anaerobic glycolysis, only relatively short-term energy needs of the cell can be satisfied.

In the body of animals and humans in the process aerobic metabolism organic substances, including products of anaerobic metabolism, are oxidized to final products - CO2 and H20. The total number of ATP molecules formed during the oxidation of 1 mol of glucose to CO2 and H20 is 25.5 mol. When a fat molecule is oxidized, more moles of ATP are formed than when a carbohydrate molecule is oxidized. So, when 1 mole of palmitic acid is oxidized, 91.8 moles of ATP are formed. The number of moles of ATP formed during the complete oxidation of amino acids and carbohydrates is approximately the same. ATP plays the role of an internal "energy currency" in the body and an accumulator of the chemical energy of cells.

The main source of recovery energy for the reaction of biosynthesis of fatty acids, cholesterol, amino acids, steroid hormones, precursors for the synthesis of nucleotides and nucleic acids is NADP H. The formation of this substance is carried out in the cytoplasm of the cell during the phosphogluconate pathway catabolism glucose. With this splitting, 12 moles of NADP H are formed from 1 mol of glucose.

Processes of anabolism and catabolism are in the body in a state of dynamic equilibrium or temporary prevalence of one of them. The predominance of anabolic processes over catabolic ones leads to growth, accumulation of tissue mass, and catabolic ones - to partial destruction of tissue structures, energy release. The state of equilibrium or non-equilibrium ratio of anabolism and catabolism depends on age. In childhood, the processes of anabolism predominate, and in senile age - catabolism. In adults, these processes are in balance. Their ratio also depends on the state of health, physical or psycho-emotional activity performed by a person.

Hello dear readers, today I would like to talk about such important concepts as anabolism, catabolism and metabolism (metabolism). Since everyone has already heard about them, but not everyone knows what they mean. So let's figure out what it is.

This is a set of chemical reactions that support the life of a living organism (reproduction and growth). Metabolism is divided into 2 types: anabolism and catabolism, so one cannot exist without the other. To make it clearer, consider metabolism using the example of a living being (human, animal, etc.):

In the process of evolution, living organisms have learned to survive due to the fact that they have developed a mechanism for the accumulation and burning of internal matter (anabolism and catabolism). This can be imagined as a solar-powered unit. There is a sun, everything is spinning and spinning, and excess energy is stored in batteries (anabolism). No sun, batteries start working (catabolism). And if there is no sun for a long time, then our mechanical prototype of the human body will stop.

Therefore, life is arranged almost like this, if we consider it as a first approximation. Our body is based on the same principle that even if, after a long period of not receiving energy (food), it will not fail. Living beings have learned to partially destroy themselves, using the released energy to continue moving in order to find food. So far, scientists have not been able to make such a mechanism in the laboratory and, probably, they will not learn soon. Nature took a long time to do this...

Anabolism and catabolism

Now that everything is roughly clear with metabolism, let's deal with the terms anabolism and catabolism.

Anabolism is the process of creating (synthesis) of new substances, cells and tissues. For example, the creation of muscle fibers, new cells, the accumulation of fats, the synthesis of hormones and proteins.

Catabolism is the reverse process of anabolism, that is, the breakdown of complex substances into simpler ones, and the breakdown of tissues and cells. For example, the breakdown (destruction) of fats, food, and so on.

You don't have to be a visionary to understand that these two processes must balance each other. Therefore, only then will a living being be able to maintain its health and life. At this point, one could pause and ask oneself, why do I need to know all this? Everything is so well arranged.

That's true, but there are restless people who really want to break this balance in order to get, for example, an increase in muscle mass. They are ready to spend hours working out in the gyms to increase their biceps or oblique muscle. Even a special sport was invented for this - bodybuilding. So, if a person, while practicing, imagines a little that this is one thing happening inside his body, and when he does it out of ignorance, this is another.

There are also many situations in life that you want to somehow explain in order to understand and make the right decision. Let's take a simple example: a young and slender girl, eats everything and does not gain weight. A couple of decades passed, and suddenly everything changed - she gained weight.

And this is due to the fact that over the years, metabolic processes (metabolism) slow down, and this leads to the accumulation of excess weight, if you do not take care of yourself properly (proper nutrition and an active lifestyle). However, not everyone does this, there are lucky people who eat everything all their lives, do not play sports and remain slim ...

Anabolic steroid

These are hormonal drugs that are used by athletes to increase muscle mass, but these drugs are very dangerous for health. Since they interfere with the anabolic process, that is, the creation of new cells and tissues, which leads to a violation of the hormonal background (hormonal system). As a result of such an intervention, health problems may arise, such as the heart, liver and kidneys.

But there are also "catabolic" steroids, which are used in medicine to treat various serious diseases, but they are also used by athletes for accelerated fat burning (drying). They are also harmful and interfere with the hormonal system, the action of such drugs is the opposite of the action (inversely proportional) of anabolic ones. Therefore, go in for “clean” sports without any drugs and be healthy.

Summarize. Metabolism is a process of chemical reactions that supports life (reproduction and growth), and metabolism consists of two components: anabolism (the creation of new substances and cells) and catabolism (the breakdown of complex substances into simpler ones). And one cannot exist without the other (anabolism and catabolism), since balance (equilibrium) is life (harmony). Do "clean" sports without any anabolic and catabolic drugs that ruin your health.

Go in for sports, eat right - success to you!

In this comprehensive guide, you will learn about the role of anabolism and catabolism in the physiological and hormonal processes that affect muscle growth and loss.

"Anabolism" and "catabolism" are perhaps the most commonly used terms in bodybuilding. However, most people are not really well versed in the processes that they denote, but only know that the first refers to the synthesis of new structures, and the second to their destruction.

Given the above, many athletes focus on improving body composition and muscle hypertrophy, and burning fat is often their main goal. Therefore, it seems reasonable to me to talk about exactly what role anabolism and catabolism play in these processes, as well as in the work of the body as a whole.

This guide will discuss the basic principles of the functioning of the human endocrine system and their impact on protein anabolism and catabolism. The metabolism of carbohydrates and fatty acids will be discussed in a separate article, along with the role of anaerobic and aerobic exercise.

Metabolism is one of those terms that almost every one of us knows and uses, yet only a few understand what it actually means. In this chapter, we will bridge the gaps in knowledge and understand what metabolism is in simple terms.

All living organisms are made up of the simplest particles - cells. Yes, this means that even the primitive microorganisms present in the human body are alive and consist of a huge number (100 trillion, I think) of cells, although many consist of only one. But I digress...

In these cells, chemical reactions are constantly taking place, accompanied by the absorption and release of energy. These reactions are divided into two classes, which we already mentioned in the introduction - anabolic and catabolic. In the first, energy is used to build the components of cells and molecules, and in the second, to destroy complex structures and substances.

Therefore, when we talk about metabolism, we mean the totality of all these physiological reactions inside the cell, which are necessary to maintain life. Many variables such as hormones, physical activity, nutrient availability, and energy status affect these processes, as well as when and how they occur. For now, just understand - metabolism is a very complex system of reactions in cells, during which energy is absorbed and released.

“During anabolic reactions, cellular components and molecules are synthesized, while in the course of catabolic reactions, the reverse process occurs.”

Body Composition Improvement

The goal of most athletes is to improve body composition (i.e., reduce body fat and/or increase muscle mass). The problem is that this "contradictory" process involves both weight gain and weight loss. In bodybuilding and fitness, many people become obsessed with losing fat and gaining muscle mass at the same time.

However, theoretically, these processes are mutually exclusive, since one requires an energy deficit, and the other an energy surplus. So when I see some kind of "magic" program that guarantees the simultaneous loss of fat and muscle building, I try to stay away from it, because this is a rather presumptuous claim that claims to overcome the laws of thermodynamics.

So the idea of ​​building muscle and burning fat at the same time is best represented as a swing (board on a stand) - if one side goes up, then the other must go down.

That is why the traditional approach of many athletes looking to improve body composition is to alternate periods of muscle building and fat loss. Colloquially, these processes are called "mass" and "drying", respectively. There is also a maintenance period when the athlete does not gain/lose muscle mass and fat.

So let's now take a look at the role anabolism and catabolism of proteins play when it comes to improving body composition.

Protein and skeletal muscle building

Skeletal muscle tissue is the largest "store" of amino acids in the human body. Many bodybuilders and healthy lifestyle enthusiasts love to talk about protein intake, mainly because this macronutrient provides the “building blocks” (amino acids) needed for muscle tissue synthesis.

However, people often misinterpret information on this subject. In fact, proteins are the most important macromolecules that play many important roles in the human body. They are related not only to the synthesis of muscle tissue, but also take part in many other processes:

• Protein metabolism of the body as a whole - protein synthesis and breakdown in all organs, including skeletal and other muscles
• Protein metabolism in skeletal muscle - protein synthesis and breakdown that occurs only in skeletal muscle

As you may have guessed, when it comes to improving body composition, we are intentionally building skeletal muscle tissue, not any other. This does not mean that the overall protein synthesis in the body plays a negative role (as in fact it is vital for existence), but its exorbitant levels for a certain period of time can lead to organ enlargement and health problems.

Synthesis, breakdown, metabolism, anabolism, catabolism and hypertrophy

• Muscle protein synthesis - protein synthesis occurring in skeletal muscle tissue
• Muscle protein breakdown - protein breakdown that occurs exclusively in skeletal muscle tissue
• Protein metabolism - the balance between protein synthesis and protein breakdown
• Protein anabolism in muscle is the state of muscle tissue in which protein synthesis exceeds protein breakdown, and where the muscles therefore increase in size.
• Protein catabolism in muscles is a state of muscle tissue in which protein breakdown exceeds its synthesis, and when muscles, therefore, decrease in size.
• Hypertrophy - overgrowth of tissue (usually applied to muscles)
• Atrophy - a decrease in muscle volume, shrinkage (the opposite process of hypertrophy)

Major hormones and factors related to protein anabolism and catabolism in skeletal muscle

So, we come to the main topic of this guide. Now is the time to talk about which factors play the biggest role in protein anabolism and catabolism, which ultimately affects body composition. As mentioned earlier, during anabolic reactions, cellular components and molecules are formed, while during catabolic reactions, everything happens the other way around. Let me also remind you that anabolic reactions require energy, and catabolic reactions are accompanied by its release. Both processes are of great importance in building skeletal muscle tissue - one of the most important aspects of improving body composition.

Here is a list of topics that will be discussed further:

• Amino acid pool, transport and oxidation of amino acids
• Insulin
• Insulin-like growth factor-1 (IGF-1) and insulin-like growth factor-binding protein-3 (IGFBP-3)
• A growth hormone
• Androgenic hormones
• Estrogen hormones
• Thyroid hormones
• "Stress hormones" - glucocorticoids, glucagon and catecholamines

Remember that many of the hormones and factors discussed in this guide interact in certain ways with each other that are almost impossible (or at least impractical) to ignore, especially in everyday life.

Amino acid pool, transport and oxidation of amino acids

As noted earlier, muscle tissue serves as the body's largest "storage" of amino acids, as well as a large amount of protein. There are 2 main amino acid pools that we are currently interested in - circulating and intracellular.

When the body is in a state of starvation (and other catabolic states), amino acids are released from the muscles into the bloodstream to fuel the rest of the body's tissues. Conversely, when protein anabolism is needed, amino acids are actively transported from the bloodstream into the intercellular space of muscle cells and are integrated into proteins (thus synthesizing new ones).

That is, in addition to intracellular amino acids, protein synthesis/anabolism is also partially regulated by the transport of amino acids both into and out of muscle cells.

In animals (mostly carnivores), amino acids provide sufficient energy through oxidation. Oxidation of amino acids to ammonia, followed by the formation of a carbon skeleton, occurs with excessive protein in the diet, starvation, carbohydrate restriction, and/or diabetes mellitus.

Ammonia is excreted from the body as urea through the kidneys, while the amino acid carbon skeletons enter the citric acid cycle for energy production. Some people oppose the traditional "bodybuilder's diet" and argue that high protein intake is taxing on the kidneys. However, even a protein intake of more than 4 grams per 1 kilogram of lean body mass does not pose any danger to people with healthy kidneys (although this is an excessive amount for most natural athletes).

"Estrogens increase growth hormone and IGF-1 levels, which is beneficial for protein anabolism and anti-catabolism"

Insulin

Insulin is a peptide hormone produced by the pancreas, primarily in response to an increase in blood sugar levels (since it acts as a regulator of glucose transporter proteins). With the sharp increase in the incidence of type 2 diabetes in the United States, insulin, unfortunately, has become notorious as almost the main enemy of mankind.

However, if your goal is to create a lean and muscular body, then insulin will serve you well. Take advantage of its anabolic properties, and don't avoid it at all costs, as many anti-carb opponents suggest.

Insulin is one of the most powerful anabolic hormones in the human body. It activates protein synthesis throughout the body with sufficient amino acid replenishment. The key point here is that a state of hyperinsulinemia (elevated insulin levels) without the concomitant presence of amino acids does not lead to an increase in protein synthesis throughout the body (although it does reduce the rate of protein breakdown).

Also, while insulin reduces the rate of protein breakdown throughout the body, it does not modulate the ubiquitinating system responsible for regulating muscle protein breakdown.

Studies show that insulin does not directly change the rate of transmembrane transport of most amino acids, but rather increases muscle protein synthesis based on the active intracellular pool of amino acids. The exception to this rule are amino acids that use the sodium-potassium pump (predominantly alanine, leucine and lysine) because insulin causes skeletal muscle cells to hyperpolarize by activating these pumps.

This suggests that the state of hyperinsulinemia in parallel with the state of hyperaminoacidemia (increased plasma amino acid content) should be sufficiently favorable for muscle protein synthesis. That is why patients with extreme malnutrition are often given injections of amino acids and insulin.

Summary:

Insulin is an anabolic hormone that promotes protein synthesis in skeletal muscle, but amino acids are required to achieve this effect.

As noted above, the state of hyperinsulinemia and hyperaminoacidemia will promote muscle protein synthesis, and the best way to induce them is simply to consume proteins and carbohydrates.

However, do not assume that the more insulin, the better. Studies show that while this hormone boosts muscle protein synthesis after a meal, there is a point of satiety where it no longer provides a more intense response.

Many people find that a huge serving of fast carbohydrates along with whey protein is ideal for activating muscle protein growth, especially after strength training. In fact, you shouldn't be trying to achieve a spike in insulin levels. A slow, gradual insulin response (as seen when loading low glycemic carbohydrates) provides the same benefits for muscle protein synthesis as a fast one.

Insulin-like growth factor-1 (IGF-1) and insulin-like growth factor-binding protein-3 (IGFBP-3)

IGF-1 is a peptide hormone, very similar in molecular structure to insulin, which affects the growth of the body. It is produced mainly in the liver when binding growth hormone and acts on some tissues both locally (paracrine) and systemically (endocrine). Thus, IGF-1 is a mediator of the influence of growth hormone and affects the growth and proliferation of cells.

In this context, it is also important to consider the action of IGFBP-3, since almost all IGF-1 is associated with one of the 6 protein classes, and IGFBP-3 accounts for about 80% of all these bindings.

IGF-1 is believed to have an effect on protein metabolism similar to insulin (at high concentrations) due to its ability to bind and activate insulin receptors, although to a much lesser extent (about 1/10 of the effect of insulin).

Therefore, it is not surprising that IGF-1 promotes protein anabolism in skeletal muscle and the body as a whole. The unique feature of IGFBP-3 is that it prevents skeletal muscle atrophy (i.e., it has an anti-catabolic effect).

Summary:

Since IGF-1 and IGFBP-3 stimulate protein anabolism and prevent skeletal muscle atrophy and cachexia, many of you may be wondering how to increase blood levels of these structures?

Well, the amount of IGF-1 and IGFBP-3 (as well as growth hormone) in the blood at any given time is influenced by several factors at once, including genetics, jet lag, age, exercise, nutrition, stress, disease, and ethnicity.

Many may assume that an increase in insulin levels will lead to a subsequent increase in IGF-1, but this is not so (remember - insulin and IGF-1 are somewhat similar in structure, but are produced differently). Since IGF-1 is ultimately produced by growth hormone (approximately 6-8 hours after entering the bloodstream), it is wiser to focus on increasing the level of the latter (which we will discuss in the section on growth hormone).

And one more note. In recent years, some supplement manufacturers have tried to convince us that deer antler extract promotes skeletal muscle growth and recovery due to the high amount of IGF-1 it contains. Do not believe these words, since IGF-1 is a peptide hormone, and when taken orally, it will be quickly broken down in the gastrointestinal tract before it enters the bloodstream. It is for this reason that type 2 diabetics are forced to inject insulin (also a peptide hormone) rather than taking it in pills or other similar forms.

“Cortisol is often involved in the muscle wasting process as it primarily acts as a catabolic hormone in terms of its metabolic functions.”

A growth hormone

Growth hormone (GH) is a peptide hormone produced by the pituitary gland that stimulates cell growth and reproduction. If a person eats well, then GH causes the production of insulin in the pancreas, as well as IGF-1, as soon as it reaches the liver, which subsequently leads to an increase in muscle mass, adipose tissue and the replenishment of glucose stores. During fasting and other catabolic states, GH preferentially stimulates the release and oxidation of free fatty acids for use as an energy source, thereby preserving lean body mass and glycogen stores.

Many “fitness gurus” misunderstand GH, claiming that it is not anabolic or even medically beneficial (which sounds pretty presumptuous given the amount of scientific evidence for this hormone). In fact, GH has a number of anabolic actions, but they are different from those of insulin. GH can be considered as the main anabolic hormone during stress and starvation, while insulin is such during the preprandial period.

Summary:

GH is a very complex hormone that is being actively studied by scientists today, since many of its properties remain unclear.

GH is a powerful hormone that stimulates protein synthesis and reduces protein breakdown throughout the body. It is likely that these effects can be induced in skeletal muscle tissues as well as by elevated levels of IGF-1 (hopefully, research will focus on this aspect in the coming years).

In addition, GH strongly inhibits the oxidation process and enhances the transmembrane transport of important amino acids such as leucine, isoleucine and valine (branched chain). It should also be noted that GH is a major factor influencing fat burning, as it promotes the use of free fatty acids as an energy source.

As noted above in the section on IGF-1, many variables affect the volume and timing of GH secretion. Considering that GH is secreted in a “pulse” mode (about 50% of the total daily production occurs during deep sleep), it is reasonable to consider the following list of its stimulants and inhibitors:

GH Stimulants:

• Sex hormones (androgens and estrogens)
• Peptide hormones such as ghrelin and growth hormone releasing peptides (GHRH)
• L-DOPA, precursor of the neurotransmitter dopamine
• Nicotinic acid (vitamin B3)
• Nicotinic receptor agonists
• Somatostatin inhibitors
• Hunger
• Deep sleep
• intense exercise

GH production inhibitors:

• Somatostatin
• hyperglycemia
• IGF-1 and GR
• Xenobiotics
• Glucocorticoids
• Some sex hormone metabolites such as dihydrotestosterone (DHT)

“The idea of ​​building muscle and burning fat at the same time is best represented as a swing (board on a stand) - if one side goes up, then the other must go down”

Androgenic hormones

Many of you are probably familiar with the term "anabolic androgenic steroids" (AAS) used frequently in the media and fitness community. Androgens are indeed anabolic hormones that affect the development of male reproductive organs and secondary sexual characteristics.

There are several androgens produced in the adrenal glands, but we will focus only on testosterone (it is mainly produced in the testes of men and the ovaries of women), since it is the main male sex hormone and the most powerful natural, endogenously produced anabolic steroid.

There is ample evidence that testosterone plays a key role in the growth and maintenance of skeletal muscle tissue. Studies have shown that the use of testosterone-based drugs in men with hypogonadism causes a rather dramatic increase in muscle tissue, skeletal muscle strength and protein synthesis. A similar effect was achieved in athletes and normal healthy people after administration of pharmacological doses of various androgens.

It seems that testosterone, like growth hormone, has an anabolic effect by reducing the oxidation state of amino acids (in particular leucine) and increasing their absorption in the body as a whole, as well as by skeletal muscle proteins.

In addition, testosterone and growth hormone create a synergistic anabolic effect, enhancing their effect on protein synthesis in skeletal muscle.

Summary:

There are many reasons why testosterone and other androgens are so well understood. It is clear that these compounds have numerous anabolic properties. Testosterone is a strong inhibitor of amino acid oxidation and increases protein synthesis in both skeletal muscle and the body as a whole (and also appears to have an antiproteolytic effect). As with growth hormone and IGF-1, many factors play a role in modulating endogenous testosterone secretion. Below is a short list of some of them.

Positive factors:

• Enough sleep
• Decrease in fat levels (to a certain extent, since fat cells secrete aromatase)
• Intense exercise (especially strength training)
• d-Aspartic Acid Supplements
• Vitamin D supplements
• Abstinence (for about 1 week)

Negative factors:

• Obesity
• Lack of sleep
• Diabetes mellitus (especially type 2)
• Sedentary lifestyle
• Extremely low calorie diet
• Prolonged aerobic/cardio exercise
• Excessive alcohol consumption
• Xenobiotics

Estrogen hormones

Estrogens are the main female sex hormones that are responsible for the growth and maturation of reproductive tissues. In the body of men, they are also present, although in much lower concentrations. There are three main estrogens produced during steroidogenesis: estradiol, estrone, and estriol. According to its effects, estradiol is about 10 times more powerful than estrone and 80 times more powerful than estriol.

In women, most estrogen is produced in the ovaries through aromatization of androstenedione, while in men it is produced in small amounts in the testicles as a result of aromatization of testosterone in fat cells.

Unlike those hormones we have already discussed, estrogens seem to have both anabolic and catabolic properties in relation to protein metabolism (mainly through other hormones in the body).

Research has shown that estrogens increase GH and IGF-1 levels, both of which are beneficial for protein anabolism and anti-catabolism. In addition, estrogens retain water, which contributes to cell growth and, therefore, the anabolic process.

However, when present in excess, estrogens can indirectly induce catabolism by blocking androgen receptors and downregulating gonadotropin-releasing hormone production in the hypothalamus, which ultimately leads to a decrease in testosterone production in the body.

Summary:

As with everything related to health and fitness, estrogen levels need to be balanced. Estrogens play many important roles in the human body, including a number of anabolic/anti-catabolic effects on protein metabolism.

Be careful, because excess estrogen (especially in men) usually leads to a decrease in the secretion and availability of testosterone, which prevents its positive effect on protein metabolism.

Here are some general tips to help you balance your estrogen production:

• Eat a balanced diet with enough vitamins, minerals and fiber
• Limit soy and plant-based phytoestrogens
• Limit alcohol intake as it impairs the liver's ability to metabolize estrogens
• Exercise Regularly
• Maintain a healthy body weight, avoid underweight or obesity

Thyroid hormones

Thyroid hormones are one of the main regulators of metabolism, affecting almost every cell in the human body. The thyroid gland produces thyroxine (T4) and triiodothyronine (T3), while T4 is a prohormone of T3. T3 is about 20 times more potent than T4 and is therefore considered the "true" thyroid hormone (most T3 comes from T4 deiodination).

Research data suggest that thyroid hormones increase both protein synthesis and breakdown throughout the body. At the same time, they stimulate the latter more actively, which means they have a catabolic effect.

In general, thyroid hormones in the normal physiological range play a major role in the regulation of protein metabolism. There does not appear to be any benefit to skeletal muscle or protein anabolism in increasing thyroid hormone production in order to achieve a state of hyperthyroidism, which likely has a catabolic effect.

Summary:

Since the main purpose of this article is to talk about hormones and factors that affect protein metabolism, this section did not mention the role of thyroid hormones in the process of fat and carbohydrate metabolism. Just be aware that the catabolic nature of thyroid hormones means that they will be conducive to fat loss due to upregulation of metabolism (which is why many people with hyperthyroidism tend to be underweight and/or have difficulty gaining weight).

However, if your goal is to achieve anabolism (especially in skeletal muscle), you should not manipulate your thyroid hormone levels. The best solution for you to support proper protein metabolism is to maintain a euthyroid state (that is, the norm).

"Stress hormones" - glucocorticoids, glucagon and epinephrine

The term "stress hormones" is often used in the literature to refer to glucocorticoids (primarily cortisol), glucagon, and catecholamines (particularly epinephrine/adrenaline). This is primarily due to the fact that their secretion is stimulated in response to stress (note that stress is not always a bad thing, and is not synonymous with the word "trouble").

Glucocorticoids belong to a class of steroid hormones produced in the adrenal glands. They regulate metabolism, development, immune function and cognitive processes. The main glucocorticoid produced in the human body is cortisol. Cortisol is an essential hormone needed to sustain life, but like many other hormones, too much or too little can be detrimental to the body.

Cortisol is often involved in the process of muscle wasting as it primarily acts as a catabolic hormone in terms of its metabolic functions. During periods of malnutrition / starvation, it maintains the nominal concentration of glucose in the blood, initiating gluconeogenesis. Often this happens at the expense of the breakdown of proteins, in order to use amino acids as a substrate for this process.

Glucagon is a peptide hormone produced in the pancreas. It mainly works in the opposite direction to the action of insulin (for example, it stimulates the release of glucose from the liver into the blood when the level of sugar in the latter falls). Similar to cortisol, glucagon influences gluconeogenesis and glycogenolysis.

The last hormone in this "triad" is epinephrine / adrenaline (sometimes also called the fear hormone). It is produced in the central nervous system and adrenal glands and affects almost all tissues of the body by acting on adrenoceptors. Like cortisol and glucagon, adrenaline stimulates glycogenolysis in the liver and muscles.

In response to injections of stress hormones, the rate of protein synthesis in skeletal muscle tissue decreases dramatically. Apparently, with prolonged exposure to stress hormones, muscle protein synthesis is disrupted, which leads to muscle tissue atrophy.

It should also be noted that adrenaline and cortisol can inhibit insulin secretion, and remember that insulin is an anabolic hormone. According to some studies, cortisol inhibits the synthesis of IGF-1, which, as already mentioned, is counterproductive for protein anabolism.

Summary:

Stress hormones are not "bad" and should not be avoided or suppressed at all costs as they are essential in many aspects of life.

Studies show that injections of these hormones promote protein breakdown in most body tissues and stimulate amino acid oxidation. They can also interfere with protein synthesis through chronic exposure and surges of insulin and IGF-1. The combination of these actions ultimately leads to a catabolic effect.

However, don't misinterpret that last statement and assume that the spikes in these hormones (which happens as a result of extreme stress) are detrimental to muscle growth. Stress hormones are an integral part of human physiology. If you have abnormally high levels of cortisol, glucagon and adrenaline in your blood for long periods of time (for example, with Cushing's syndrome, chronic stress, etc.), then you probably do not need to worry about their spikes, as this is not not only inappropriate, but also harmful.

Conclusion

Although this article is replete with scientific terms, I hope it has shed some light on the major factors that affect protein metabolism. This is a complex topic, and protein metabolism is an ever-evolving area of ​​research, but it needs to be analyzed and discussed.

The article does not encourage the use of the compounds or hormones mentioned in it without the permission and supervision of a qualified specialist. The information contained herein is intended to be used to manipulate hormone levels in an endogenous rather than exogenous manner.

Finally, remember that many physiological processes are very complex. It is important to always take into account the circumstances and context of the situation. It is impractical and unwise to forget the importance of a person's personality when giving advice on diet and exercise.

This guide aims to explain the factors that affect protein metabolism and give you, dear reader, the information that will help you build the optimal nutrition program and lifestyle needed to achieve your goals.

13.4.1. The Krebs cycle reactions are the third stage of nutrient catabolism and occur in the mitochondria of the cell. These reactions belong to the general pathway of catabolism and are characteristic of the breakdown of all classes of nutrients (proteins, lipids and carbohydrates).

The main function of the cycle is the oxidation of the acetyl residue with the formation of four molecules of reduced coenzymes (three NADH molecules and one FADH2 molecule), as well as the formation of a GTP molecule by substrate phosphorylation. The carbon atoms of the acetyl residue are released as two CO2 molecules.

13.4.2. The Krebs cycle includes 8 successive stages, paying particular attention to the dehydrogenation reactions of substrates:

Figure 13.6. Krebs cycle reactions, including the formation of α-ketoglutarate

a) condensation of acetyl-CoA with oxaloacetate, as a result of which citrate is formed (Fig. 13.6, reaction 1); so the Krebs cycle is also called citrate cycle. In this reaction, the methyl carbon of the acetyl group interacts with the keto group of oxaloacetate; cleavage of the thioether bond occurs simultaneously. The reaction releases CoA-SH, which can take part in the oxidative decarboxylation of the next pyruvate molecule. The reaction is catalyzed citrate synthase, it is a regulatory enzyme, it is inhibited by high concentrations of NADH, succinyl-CoA, citrate.

b) conversion of citrate to isocitrate through the intermediate formation of cis-aconitate. The citrate formed in the first reaction of the cycle contains a tertiary hydroxyl group and is not capable of being oxidized under cell conditions. Under the action of an enzyme aconitase there is a splitting off of a water molecule (dehydration), and then its addition (hydration), but in a different way (Fig. 13.6, reactions 2-3). As a result of these transformations, the hydroxyl group moves to a position that favors its subsequent oxidation.

in) isocitrate dehydrogenation followed by the release of a CO2 molecule (decarboxylation) and the formation of α-ketoglutarate (Fig. 13.6, reaction 4). This is the first redox reaction in the Krebs cycle, resulting in the formation of NADH. isocitrate dehydrogenase, which catalyzes the reaction, is a regulatory enzyme, activated by ADP. Excess NADH inhibits the enzyme.

Figure 13.7. Krebs cycle reactions starting with α-ketoglutarate.

G) oxidative decarboxylation of α-ketoglutarate, catalyzed by a multienzyme complex (Fig. 13.7, reaction 5), accompanied by the release of CO2 and the formation of a second NADH molecule. This reaction is similar to the pyruvate dehydrogenase reaction. The inhibitor is the reaction product, succinyl-CoA.

e) substrate phosphorylation at the level of succinyl-CoA, during which the energy released during the hydrolysis of the thioether bond is stored in the form of a GTP molecule. Unlike oxidative phosphorylation, this process proceeds without the formation of the electrochemical potential of the mitochondrial membrane (Fig. 13.7, reaction 6).

e) succinate dehydrogenation with the formation of fumarate and the FADH2 molecule (Fig. 13.7, reaction 7). The enzyme succinate dehydrogenase is tightly bound to the inner mitochondrial membrane.

and) fumarate hydration, as a result of which an easily oxidized hydroxyl group appears in the molecule of the reaction product (Fig. 13.7, reaction 8).

h) malate dehydrogenation, leading to the formation of oxaloacetate and the third NADH molecule (Fig. 13.7, reaction 9). The oxaloacetate formed in the reaction can be reused in the condensation reaction with the next acetyl-CoA molecule (Fig. 13.6, reaction 1). Therefore, this process is cyclical.

13.4.3. Thus, as a result of the described reactions, the acetyl residue undergoes complete oxidation CH3 -CO-. The number of acetyl-CoA molecules converted in mitochondria per unit time depends on the concentration of oxaloacetate. The main ways to increase the concentration of oxaloacetate in mitochondria (relevant reactions will be discussed later):

a) carboxylation of pyruvate - the addition of a CO2 molecule to pyruvate with the expenditure of ATP energy; b) deamination or transamination of aspartate - cleavage of the amino group with the formation of a keto group in its place.

13.4.4. Some metabolites of the Krebs cycle can be used to synthesis building blocks for building complex molecules. Thus, oxaloacetate can be converted to the amino acid aspartate, and α-ketoglutarate can be converted to the amino acid glutamate. Succinyl-CoA is involved in the synthesis of heme, the prosthetic group of hemoglobin. Thus, the reactions of the Krebs cycle can participate both in the processes of catabolism and anabolism, that is, the Krebs cycle performs amphibolic function(see 13.1).