The role of liver in metabolism: an updated review with physiological emphasis

ABSTRACT

Liver plays an essential role in metabolism and has an important role in preserving and regulating the levels of lipid, glucose in the body as well as energy metabolism. Among the important functions performed by the liver is maintaining of blood glucose levels under different conditions through group of processes included; glycolysis, glycogenesis, glycogenolysis, gluconeogenesis. The absorbed free fatty acids and those derived from the adipose tissue reach the liver and are utilized for energy, membrane synthesis, or stored as triglyceride. In addition, the liver has a crucial role in keeping homeostasis of body level of cholesterol. Regarding protein metabolism, urea cycle occurs in the liver through the action of urea cycle enzymes to produce urea in order to get rid of the toxic ammonia. In the liver, cholesterol is utilized for bile acids synthesis through a complicated process. These bile acids are considered essential in order to absorb and transport of lipid-soluble vitamins dietary and fat in the diet as well as clearance of drugs, toxic substances and xenobiotics. Adding to these hepatic functions is hepatic detoxification where liver metabolizes a various type of drugs to make soluble execretable compounds. In conclusion, the liver has so important metabolic functions which if impaired will resulted in many liver diseases and might progress to more dangerous conditions such as liver fibrosis or cirrhosis.