Cholesterol is a fat-like substance from the group of sterols; first isolated from bile and brain tissue. Crystals with a temperature of melting of 149 degrees. Cholesterol is insoluble in water but soluble in organic solvents. Cholesterol is found in all body tissues and in the blood plasma. Normal cholesterol in the blood is 150-200 mg% . In some pathological conditions, the concentration of cholesterol in the blood can vary in either direction (see Cholesterolemia). The body gets from food, is well absorbed in the intestine only in the presence of bile.
Cholesterol is involved in the metabolism of biologically important sterols, such as hormones crust napochechnikov, provitamin D3, and in regulating the permeability of the cell and the protection of erythrocytes by certain hemolytic poisons. In certain pathological conditions, such as cholecystitis, cholesterol falls out of bile in crystalline form, forming more or less large stones; the bulk (90%) of gallstones consists of cholesterol. In addition, the etiology of atherosclerosis person is typically associated with the metabolism of cholesterol.
Cm. also Sterols.

Cholesterol (synonym cholesterol formula With27N46O) - organic matter related to the group of sterols.
Cholesterol is insoluble in water, it is soluble in petroleum ether, lower alcohols, acetone, ether, acetic acid; soluble in benzene, carbon disulfide, triethylamine; temperature of melting of 149.5 degrees (net)cholesterol, temperature boiling 360 degrees (with decomposition).
Cholesterol contains one hydroxyl group in position 3β and capable of forming of simple and complex ethers. It forms a double connection with glucose and other carbohydrates, proteins, amines, oxalic acid, different salts; gives sparingly soluble compounds with various steroid saponins and glycoalkaloids. So it is used as an antidote for poisoning with saponin.
Color reactions cholesterol, characteristic of sterols. 1. Reaction Salkovsky: shake 0.01 g cholesterol in the mix 1 ml of chloroform and 1 ml of concentrated sulfuric acid; chloroform layer is painted red, and the acid's fluorescent green. 2. Sample Lieberman - Burchardt: 5 mg cholesterol dissolved in 2 ml of chloroform, add 1 ml of acetic anhydride and 1 drop of sulfuric acid. With shaking appears pink coloration, fast turning consistently in red, blue and green. For the quantitative determination of cholesterol use color reaction Lieberman-BURKHARDT with subsequent determination of the optical density (610-620 MMK). Apply a weighting method, based on the ability of cholesterol to give insoluble molecular connection with digitonin.
In some tissues of animals, for example in the nervous tissue, cholesterol is contained in a free form, in other - in the form of esters of higher fatty acids - palmitic, oleic, etc. Most cholesterol is observed in the brain, liver, kidneys and adrenal glands. In food cholesterol is contained in fats, egg yolks.
Normal cholesterol in the blood is 150-250 mg in 100 ml With atherosclerosis, diabetes number increases significantly with exhaustion and some infectious diseases decreases (see Cholesterolemia). Violation of cholesterol metabolism in the blood vessel walls are covered with cholesterol and its derivatives, which may be one of the causes of atherosclerosis. The selection of cholesterol in the body of bile into the crystalline state leads to a bile stone disease.
The majority of cholesterol is synthesized in the body and only about 20 percent comes from food.
Research with application of organic compounds containing the isotopes of carbon and hydrogen, showed that in the body of cholesterol synthesis of acetic acid. Clarified the sequence and intermediate products of numerous (about 30) stages of the biosynthesis of cholesterol, found that most of the cholesterol is synthesized by the liver. This is the body that regulates the content of cholesterol in the plasma and other bodies, and the rate of its synthesis depending on the amount of cholesterol entering the body with food.
The role of cholesterol in the body is extremely high. He is involved in a complex exchange of sterols in the body, including the formation and transformation of such importance to the body connections, as bile acids, hormones crust napochechnikov, sex hormones, provitamin D3 and so on; takes part in regulating the permeability of cells, protects red blood cells from the effects of some hemolytic poisons.
In industry cholesterol is obtained from the spinal cord of animals (containing 15% cholesterol) extraction with acetone.
Cholesterol is used as the raw product for the synthesis of steroid sex male and female hormones and hormones napochechnikov crust. Cm. also Sterols.