Metabolism of Glycerin
1.The absorption of glycerin
Glycerin is easily absorbed by human or animal stomach and intestinal mucosa. Animal slices of the small intestine of mice showed that 82% of them were absorbed after 25 minutes if 0.1 mg of glycerol was given. In the same experiment, like gastric slices, the absorption rate of glycerol is slower than that of the small intestine.Experiment on slicing of hamster intestine, the absorption rate of glycerol was 25% of glucose.
Experiments on human body: Oral glycerin 5g, when 15min, the highest concentration of glycerol in serum. For adults, it is 0.46-1.85mg/dL with a turnover speed of 550g/h. From the animal experiment of labeling glycerin with 14c, the glycerin in blood decreased rapidly after 4H of intravenous injection.
In addition, the absorbed glycerin is distributed in the brain and liver. Kidney and other body parts. Glycerin is hardly absorbed by the skin.
14% of glycerin is consumed by rabbits and rats. After 48H, the tendency of glycerol was observed: 65% of glycerol was converted to carbon dioxide and excreted by absorption, 8.4% of glycerol was excreted in urine and the rest was excreted in feces.
For the human body, if a large amount of glycerol is taken, it will not metabolize and excret directly in the urine. When taking 8.9-17.8G, there is no urinary excretion. When taking 20G, there are traces of excretion. When taking 26G, 0.5-0.1G was detected and 200G was excreted in total 200G. The excretion of urine increased by 40%-50% compared with that of oral administration.
Glycerol absorbed in the body is first converted to glycerol -3- phospholipid by the action of glycerol activating enzyme. Glycerol induced enzymes are distributed in liver, kidney, heart or mammary gland. Glycerol -3- phospholipid is the intermediate product of sugar metabolism.
- Glycerol-3-phospholipid has the same metabolic effect as sugar. It is decomposed into water and carbon dioxide through TCA cycle, or vice versa to produce glucose and glycogen for new glucose metabolism. It has been reported that 75% of glycerol in serum changes to glucose.
The metabolism of glycerin in the body becomes the source of energy supply, and the heat generated is 4.32Kcal/g
(2) glycerol -3- phosphoric acid was converted to monoglyceride, Diglycerin, three glyceride and phospholipid.
(3)After transporting glycerol-3-phosphate from cytoplasm to glandular granules, glycerol-3-phosphate dehydrogenated to dihydroxyketone phosphate due to the action of enzymes, FADH was produced at this time, but FADH was utilized as an electron donor of oxidative phosphorylation in glandular granules, which is a well-studied and proven way.
Glycerol in the body can increase insulin, but unlike hexose such as glucose, the effect of insulin is not affected. In addition, glycerol has the effect of preventing ketone formation and preventing the production of acetic acid and other ketone bodies. In addition, the role of glycogen amino acids in the production of new sugars is also prevented.