Biochemistry

Intestinal cavity ------ Triacylglycerols ------- Diacyl ^lycerols ---- Monoacylglycerols „ I — ---- > Fatty acids Glycerol The mucous membrane of the small intestine -------------------------------- > -* Triacylglycerols * ----- Phosphoglyceride; \ ,, Glycerol phosphate -< 1 Glucose Vascular ( Ю-30% \ X / 10-30% \ bed V of all fats 7/ \ ( ofalIfats ) Glucose Lymph SI Blood /Л ; Figure 10.3 - The transformation of lipids in the small intestine Of all the lipoproteins in blood plasma, low and very low density ft-lipoproteins are atherogenic. They are able to penetrate into the vascular wall from blood plasma, being the primary substrate causing atherosclerotic damage to the arteries. With atherosclerosis, the level of cholesterol in the blood rises by 2-5 times (sometimes up to 13 mmol / 1). The cause of hypercholesterolemia is an imbalance between the amount of cholesterol that is broken down and synthesized. The main role in the occurrence of hypercholesterolemia belongs to endogenous cholesterol. The increase in this indicator was observed with excessive consumption of fats and carbohydrates and impaired utilization of acetyl-CoA. Cholesterol from acetyl-CoA is also synthesized in the liver. The activity of this process depends on the amount of exogenous cholesterol supplied with food. Biosynthesis of cholesterol in the liver is regulated according to the principle of negative feedback: the more it comes from food, the less it is synthesized in the liver, and vice versa. Part of the synthesized cholesterol is converted into bile acids and is excreted from the body with bile, in addition it is used to synthesize steroid hormones and other compounds. In the liver, it interacts with fatty acids to form esters that enter the blood. In the liver the breakdown and synthesis of phospholipids happens. For its synthesis, in addition to glycerol and higher fatty acids, inorganic phosphates and nitrogenousbases, in particular choline, are necessary. Inorganic phosphates in the liver are contained in sufficient quantities, and choline is small, so it must necessarily come from food. 194