Fat metabolism (lipid metabolism) - is a set of processes of transformation of fats in the body. There are three stages of fat metabolism: 1) the breakdown and absorption of fat in the gastrointestinal tract; 2) the transformation of absorbed fat in the tissues of the body; 3) isolation of fat metabolism products from the body. The main part of edible fats (see) is subjected to digestion in the upper intestines with the participation of the lipase enzyme secreted by the pancreas and intestinal mucosa. Cleavage produces a mixture of fatty acids, di- and monoglycerides.
The process of splitting and absorption of fats and other lipids (see) contributes to the excretion of bile acids in the intestine (see), due to which the fats become emulsified. Part of the fat is absorbed in the intestine in undigested form. Absorbed fatty acids are partly used in the intestinal mucosa for the resynthesis of triglycerides and phospholipids, and part of the portal vein or lymphatic vessels pass into the blood.Go
The amount of neutral fats and fatty acids in the blood is variable and depends on the intake of fats from food and on the rate of fat deposition in the fat depots (see Lipemia). The total fat content in the blood of adults averages 720 ± 200 mg%, neutral fat 225 ± 140 mg%, fatty acids 350 ± 150 mg%. In tissues, fats are broken down by various lipases, and the resulting fatty acids form part of other compounds (phospholipids, cholesterol esters , etc.) or are oxidized to final products. The oxidation of fatty acids is accomplished in several ways. During oxidation in the liver, part of the fatty acids produces acetoacetic and (β-hydroxybutyric acids, as well as acetone (see Acetone bodies). In severe diabetes mellitus , lipoid nephrosis, and others. The amount of acetone bodies in the blood increases dramatically. products of fat metabolism, as well as products of carbohydrate and protein metabolism.Fat metabolism disorders can be divided into the following groups: 1) violation of fat absorption, its deposition and formation in adipose tissue ; 2) excessive accumulation of fat in organs and tissues that are not related to adipose tissue; 3) violation of intermediate fat metabolism; 4) violation of the transition of fats from the blood to the tissue and their excretion.
See also Metabolism and energy.