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Metabolic Functions of the liver

Carbohydrate Metabolism

It is critical for all to maintain concentrations of glucose in blood within a narrow, normal range. Maintenance of normal blood glucose levels over both short (hours) and long (days to weeks) periods of time is one particularly important function of the liver.
Excess glucose entering the blood after a meal is rapidly taken up by the liver and sequestered as the large polymer, glycogen (a process called glycogenesis). Later, when blood concentrations of glucose begin to decline the liver activates other pathways which lead to depolymerization of glycogen (glycogenolysis) and export of glucose back into the blood for transport to all other tissues.When hepatic glycogen reserves become exhausted, as occurs when we haven’t eaten for several hours, do the hepatocytes give up? No! They recognize the problem and activate additional groups of enzymes that begin synthesizing glucose out of such things as amino acids and non-hexose carbohydrates (gluconeogenesis). The ability of the liver to synthesize this “new” glucose is of monumental importance.

Fat Metabolism

Few aspects of lipid metabolism are unique to the liver, but many are carried out predominantly by the liver. Some major examples of the role of the liver in fat metabolism…

The liver is extremely active in oxidizing triglycerides to produce energy. The liver breaks down many more fatty acids that the hepatocytes need, and exports large quantities of acetoacetate into blood where it can be picked up and readily metabolized by other tissues…
A bulk of the lipoproteins are synthesized in the liver…
The liver is the major site for converting excess carbohydrates and proteins into fatty acids and triglyceride, which are then exported and stored in adipose tissue…
The liver synthesizes large quantities of cholesterol and phospholipids. Some of this is packaged with lipoproteins and made available to the rest of the body. The remainder is excreted in bile as cholesterol or after conversion to bile acids.

Protein Metabolism

The most critical aspects of protein metabolism that occur in the liver are:
Deamination and transamination of amino acids, followed by conversion of the non-nitrogenous part of those molecules to glucose or lipids. Several of the enzymes used in these pathways (for example, alanine and aspartate aminotransferases) are commonly assayed in serum to assess liver damage…🤔
Removal of ammonia from the body by synthesis of urea. Ammonia is very
toxic and if not rapidly and efficiently removed from the circulation, will result nervous system disease (cleaning products anyone)… A frequent cause of such hepatic
encephalopathy in dogs and cats are malformations of the blood supply to the liver called portosystemic shunts…
Hepatocytes are responsible for synthesis of most of the plasma proteins. Albumin, the major plasma protein, is synthesized almost exclusively by your liver……..

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