Anabolism

“ The dual processes of metageneses, which are evolution and dissolution, are now combined so long as life lasts. In rest, and especially in sleep, anabolism may progress at a greater rate than catabolism; in exercise, and especially in violent exercise, catabolism may prevail, but neither can wholly cease while the motile state endures. ”

“ Woman's resistance to death is thus more marked at the two extremes of life, infancy and old age, the periods in which her anabolism is uninterrupted. Menstruation, reproduction, and lactation are at once the cause of an anabolic surplus and the means of getting rid of it. At the extremes of life no demand of this kind is made on woman, and her anabolic nature expresses itself at these times in greater resistance.
Dr. Lloyd Jones has determined that between 17 and 45 years of age the specific gravity of the blood of women is lower than that of men. ”

“ First we note that metabolism consists of two correlative systems, one of anabolism, the other of catabolism; that is, the one builds up, the other tears down. They are not only correlative, but to a large extent they are contemporaneous. In fact, there can be no building up without tearing down; that is, no placement which is not displacement, except that material may be stored adjacent to organs as fatty substances, to be used as needed after it has thus been stored. ”

“ That muscles are in pairs is an anatomical fact, and that the one contracts while the other relaxes is a physiological fact, and that the mind somehow controls this muscular activity at will is a psychologic fact, and the whole thing is rendered simple and clear by the doctrine that anabolism in one muscle and catabolism in its opponent are each under the control of mind. But the mind of the cortex does not consciously choose the association of the several particles involved in metabolism. ”

“ Thus the authors' proposition that the male is the outcome of predominant katabolism, and the female of equally emphatic anabolism, might seem to be justified, and it is confirmed by the curious phenomenon of alternation of generations, and by various facts connected with growth and reproduction. ”

“ Repair and Elimination of Waste (Metabolism)
Every part of the body is constantly changing. Its work never stops. If kept in thorough repair it must be torn down and rebuilt incessantly. These chemical changes are called collectively metabolism. They are divided into two groups: the chemical process of building up complex substances from simple ones is known as anabolism; the chemical process of oxidizing and breaking down the complex substances into simple ones, so that they are in a state to be excreted, is catabolism. ”

“ The body converts potential into kinetic energy by metabolism in the body. The potential energy of food is transformed into the actual energy of heat and mechanical labor. In this respect the only difference between man and other vertebrates is the nervous and intellectual processes, which are not yet understood.
Metabolism is anabolic and katabolic. Anabolism is constructive; it includes growth and the act of the tissues in selecting, appropriating, and making substances absorbed from the alimentary canal a part of themselves. The body is never stable ”

“ Besides anabolism, the accumulation of phenolic compounds could be influenced by catabolism. The accumulation of nongalloylated catechins were considered to be aroused from the hydrolysis of galloylated catechins. ”

“ In other words, when the blood stream nourishing the tissues is ideally correct, the individual cells of the body perform their functions normally, and as each cell is worn out it is removed by a healthy catabolism and renewed by a normal anabolism, and homologous cells then replace those which have ceased to be able to perform their function. ”

“ It may be impracticable to outline in terms of metabolism the precise processes of waste and repair in organs and organisms, or to define the relative periods of action and assimilation (or of catabolism and anabolism) best adapted to the development of motile tissue ”

“ A very noticeable expression of the anabolism of woman is her tendency to put on fat. "Women, as a class, show a greater tendency to put on fat than men, and the tendency is particularly well marked at puberty, when some girls become phenomenally stout."60 The distinctive beauty of the female form is due to the storing of adipose tissue, and the form even of very [pg 30] slender women is gracefully rounded in comparison with that of man. ”

“ In more general terms, growth expresses the preponderance of constructive processes or anabolism; increase of volume with less rapid increase of nutritive, respiratory, and excretory surface involves a relative predominance of katabolism; the limit of growth occurs when further increase of volume would prejudicially increase the ratio of katabolism to anabolism ”

“ For it must be recognized that all the cells of the body are continually bathed in the vitalizing fluid of the blood, whence they derive their nutriment, and into 74which, with the lymphatics, they return the products of their vital action, by anabolism and catabolism.
By exclusion, therefore, we are reduced to seek the etiology of cancer along other lines, and about all that is left is metabolism, as influenced by advancing, so-called civilization, which relates very largely to diet and mode of life. ”

“ The general term for chemical actions occurring in the tissues of a living creature is metabolism; where the change is of such a nature that complex and unstable compounds are built up and stored for a while, it is called anabolism; where complex unstable compounds break up into less complex and relatively stable compounds, the term katabolism is applied. ”

“ As is well known, the nutrition of man is supplied by the organic substances, protein, carbohydrates, and fat; these are found in various combinations in animal and vegetarian foods, and as a rule contain also much of the inorganic or mineral substances necessary for the system; all of 111these with water, and its salts, and oxygen, supplied by the lungs, unite, through anabolism and catabolism, to build and maintain the human body in health. ”

“ Oxidized carbon in the body forms carbon dioxid; hydrogen is oxidized into the form of water, while nitrogen leaves the body in the more complex and incompletely oxidized substance known as urea, the chemical formula of which is COH4N2. A small portion of nitrogen leaves the body in the form of uric acid, C5H4N4O3.
Why muscular work produces warmth
The process of anabolism usually absorbs energy or heat from the surrounding material, while catabolism produces heat as a result of oxidation, as do ordinary fuels. This explains why muscular work warms the body. ”

“ During activity the glycogen or sugar in the muscle is used up and the muscle becomes more acid, owing to the lactic acid that is formed. The carbon is taken in and carbon dioxide given off. Nitrogen puts the muscle in condition to do its work but is not so much used up in the work as is the carbohydrate material. So it is the non-nitrogenous matter that does the work and any increase in urea, the end-product of protein metabolism, is mere wear and tear.
Sudden heat or cold causes muscular contraction and moderate heat favors both muscular and nervous irritability. ”

“ The change in resting metabolism that comes about in health is one that is seen when the diet contains an especially large percentage of protein. For some reason which we do not understand the digestion, absorption, and utilization of protein stimulate the resting metabolism so that during the time that this protein is being used the metabolism is higher than at other times. The curious thing about it is that the increase of metabolism is not just enough to take care of the protein itself, but goes so far to cause sugars or even fats to be burned at a more rapid rate than usual. ”

“ It is to be noted that we are as yet entirely ignorant of the origin and significance of the creatine which is so abundant in muscles, and it is scarcely to be doubted that fundamentally important metabolism problems somehow are connected with the muscle creatine and urinary creatinine, but these are as yet problems of normal metabolism, and it is too early to say whether, or in what way, light may be thrown on clinical problems by studies of these products. The fact that the muscles of mammals, including man, contain 0·3-0·4 per cent. ”

“ This urea is carried by the blood stream from the liver to the kidneys where it is passed out to become the chief organic substance in urine. The more protein one eats the more surplus amino acids will there be, and so the more urea will be formed and passed out of the body. Flesh-eating animals and men (Eskimos for an example of the latter) eat a very large surplus of proteins, the fuel for their metabolism being furnished almost altogether either from the usable remains of the decomposed amino acids or the fats that were in the flesh they ate. ”

“ A trifling amount of urea is also eliminated in the sweat and in the breath as well as in the feces. Proteins increase nitrogenous metabolism and also the metabolism of other foods, but the amount of nitrogen eliminated is just equal to that taken in. Probably some comes from the tissues themselves and not from the food. The oxidation of carbohydrates and fats is measured by the amount of carbon excreted. At first as much is given off as is taken in, but after a while the carbohydrate is stored up as glycogen in the liver and the fats are stored as fat. ”

“ There is not the slightest doubt that the course of this metabolism, as well as the inter-relations of the cells of a particular organ, is only imaginable under the supposition that the metabolism of the whole organism is regulated in the most precise way, not only quantitatively, but also qualitatively. We are bound to imagine that, in the work of the cells, the same stages of decomposition recur regularly, and that it is at a quite definite stage that the by-products of metabolism are passed by the cells into the lymph channels, and so into the blood system. ”

“ Fate of the Proteins.—After utilization in the body, the proteins, like the other foods, leave certain waste products which indicate to a greater or lesser extent the completeness with which the organism has made use of the food materials. The end-products of protein metabolism are: urea, ammonium salts, purin bodies, and creatinin. These products leave the body chiefly in the urine. The chief end-product in man is urea. This substance represents from 82-88% of the total nitrogen excreted by the kidneys. ”

“ Thus far we have spoken of hormones only in connection with their ability to excite those nerve cells by which smooth muscles and glands are controlled. As a matter of fact, their action is much wider than that. They have the power of affecting the metabolism of very many body cells. Some of them appear to have the special function of regulating the rate of metabolism. These we shall talk about in detail, when we return to the study of metabolism in a later chapter. One of the hormones is interesting in connection with the relation of emotions to smooth muscle and gland activity. ”

“ The fact is that when an average-sized human being goes on a diet which contains no protein, but is ample in other respects, he loses daily from his body about an ounce of protein. This is proven by the occurrence in the urine of an amount of nitrogen which stands for that much protein. The person may be gaining or losing weight meanwhile; if his consumption of fats, starches, and sugars is excessive, he may deposit some fat, in which case he might gain weight in spite of the loss of some of his actual living protoplasm. ”

“ Muscular Work.—The muscular tissue plays the most important part in general metabolism. Not only is muscle the most abundant tissue present, but it is constantly active and is the great energy liberating machine of the body. Formerly it was believed on the authority of Liebig that muscular work was done at the expense of the protein material, but it has been conclusively shown that the real source of energy in moderate work is the non-protein material, carbohydrates and fats; of these the former plays the greater part in a man on ordinary diet. ”

“ The organism has developed special facilities for getting rid of such excess of nitrogen, so as to get the use of the carbonaceous part of the proteid containing it.” In endogenous metabolism, we have a steady, constant process quite independent of the amount of proteid food, and absolutely indispensable for the maintenance148 of life. So far as we know at present, its representative creatinin is, for a given individual, the same in amount during fasting as when a rich, meat-free, proteid diet is taken. ”

“ As we have seen, the energy of muscle work is derived mainly, and can come wholly, from the breaking down of non-nitrogenous materials, fats and carbohydrates. The very fact that an intake of say 120 grams of proteid is followed at once by the removal of the larger part of the contained nitrogen, as a result of the exogenous katabolism of the body, would seemingly warrant the view that the proteid so decomposed might advantageously be replaced by a corresponding amount of carbohydrate. In muscle work, as in heat production, carbohydrate and fat are the materials burned up, or oxidized. ”

“ This gland is now known to manufacture and pour out into the blood a hormone which is a regulator of metabolism. When it is produced in normal amounts, the metabolism goes on at the rate that we find in healthy people. If the gland is inactive and does not secrete enough of the hormone, there is a reduction in the metabolism. Since this implies a lowering of the vigor of the life processes, we might expect it to have important effects. The most marked of these are in the nervous system. Persons whose thyroid glands are relatively inactive are mentally sluggish ”