CONTRIBUTIONS to OUR KNOWLEDGE of CH'OLESTEROL STEFAN MINOVICI
AND
M. VANGHELOVICI
The Institute of Chemistry, Bucharest, Roumania
I n this article the authors describe succinctly their for the nervous system where, according to the authors, researches on cholesterol, esficially from che physiologial it proteds and isolates nervous fibers. The metabolism point of view, which culminated recently in a partial bio- of this substance under variuus conditions is also described synthesis of this subslance. The im@rlance of choles- as well as its relationship to other substances such as bile terol for the animal organism i s pointed out especially acids, sexual hormones, saponins, heart poisons, etc.
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HOLESTEROL is widely disseminated throughout the animal kingdom. Indeed it may be said that all cells of an organism contain this substance-naturally in different proportions. The greatest amount is found in brain tissue, suprarenal glands, etc. The human brain contains considerable qnantities of this substance, ranging as high as 17% of the dry material ( 1 ) . Cholesterol belongs to the great class of the sterols which are subdivided into zoosterols, i.e., animal sterols, and phytosterols, i. e., vegetable sterols. It is evident that this substance, so widely disseminated in the living world, is of especial interest both with regard to its chemical composition and to its physiological properties. With regard to the structure of cholesterol, the following formula was established in 1932 as a result of the vast research undertaken by Windaus, Wieland, and Rosenheim (2).
properties of this substance and outline a partial biosynthesis which was accomplished in our laboratories recently. With regard to the r61e of cholesterol in the animal organism, i t was first pointed out that this substance exerts a powerful antihemolitic and antitoxic effect in antagonism to hemolitic substances and microbic toxins. For this purpose various substances were tested, such as: sera of animals of various species, venom of serpents, trypanosomes, microbic toxins, saponins, soaps, glucosides, etc. All these tests in vioo and in vitro have shown, beyond question, the importance of cholesterol as an antihemolitic and antitoxic agent. By way of illustration we shall cite only a classical experiment of Morgenroth and Reichert (4). They administered cholesterol to a guinea pig from a lot of three, the other two receiving nothing. Next day cobra venom was injected into these animals. The results were very convincing. The guinea pig which CHs received cholesterol maintained a normal blood, while I in the other two the number of erythrocytes dropped by CH.CHXHrCH1CH one-half. Such experimental findings are supplemented by the observation that in the course of various infectious /\ /diseases, such as tuberculosis, typhoid fever, and diphtheria, the blood of cholesterol decreases, evidently OH/ Cholesterol due to the tendency of cholesterol to combine with the toxins secreted by the microbes. During convalesThis formula shows clearly how extremely complicated cence, we witness an upward trend of the cholesterol is this substance containing four hydroaromatic rings content of the blood, which constitutes a favorable and a side chain of eight carbon atoms. Ring I carries diagnostic. a hydroxyl group and Rmg I1 contains a double link. On the other hand, cholesterol plays a very imporThe hydroxyl group enables cholesterol to form esters. tant r6le in the eqnilibriaof cell permeability. Indeed, During our investigations of this substance, which Overton has shown that all cells are limited by a memdate as far back as twenty years ago, we have obtained a brane composed of phosphatides and cholesterol. series of derivatives which have contributed to the Thus, when distilled water is injected in the blood elucidation of the structure of this substance, especially hemolysis takes place, which, however, does not happen with regard to the number of the carbon atoms of Ring if we first inject cholesterol. Overton, on the basis of 11, which we demonstrated to be six (3). his researches, has postulated his theory of the action of We shall not describe in detail the chemistry of anesthetics. The third remarkable property of cholesterol is its cholesterol, which would necessitate an article in itself; we shall merely point out the various physiological capacity to absorb large amounts of water (hydro637
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