Biochemistry

The whole kinin system has the ability to expand the lumen of blood vessels, relaxing their muscles, which leads to a decrease in blood pressure. The renin-angiotensin system is an antagonist of the kallikrein-kinin system. Angiotensin is synthesized in an inactive form in the form of an angiotensinogen, which is activated by the renal enzyme, renin. Through limited proteolysis, angiotensinogen is converted to angiotensin. The latter is an important regulator of the secretion of the hormone of the adrenal cortex - aldosterone, is involved in the regulation of not only vascular tone, but also water-salt metabolism. The relationship between the kinin system and the angiotensin-aldosterone- renin system is an important mechanism for the regulation of hemodynamics. Violation of this ratio can lead to an increase in blood pressure. Prostaglandins are compounds with a wide range of hormonal effects. They are synthesized from polyunsaturated fatty acids (arachidonic, linolenic, linoleic) in many body tissues, especially in the reproductive organs. Were first isolated from prostate (from Greek. Ge prostata ), hence their name. Depending on the structure of the cyclic part of the molecule, natural prostaglandins of type А, В, E, F arc distinguished . The number of double bonds in the side chains of the listed types is denoted by digital indices. Prostaglandins affect a number of biochemical reactions. They lower lipase activity, are an important regulator of calcium metabolism in muscle tissue, have an effect on renal hemodynamics, secretory' function of the stomach, and the formation of steroid hormones. Currently, prostaglandins are found in many organs and tissues, including the brain, especially in the cerebral cortex, where their biosynthesis is carried out. Gas /пи is a 17-membercd peptide synthesized by the gastric mucosa.lt increases the secretion of gastric juice (mainly stimulates the formation of hydrochloric acid and only slightly increases the production of pepsin). Gastrin also contributes to the secretion of the pancreas and enhances the tone and contraction of the muscles of the stomach and small intestine. 292