The formation of glycogen from glucose is called glycogenesis, and the breakdown of glycogen is called glycogenolysis. Thus, the liver can secrete glucose derived from glycogen. In lipolysis, triglycerides yield glycerol and fatty acids. Glycerol can be converted to phosphoglyceraldehyde and used for energy. In the process of the b -oxidation of fatty acid, a number of acetyl CoA molecules are produced.
Amino acids derived from the hydrolysis of proteins can serve as sources of energy.
In oxidative deamination, amino acids are converted into keto acids as their amino group is incorporated into urea. Each organ uses certain blood-borne energy carriers as its preferred energy source. The brain has an almost absolute requirement for blood glucose as its energy source. The McGraw-Hill Companies. All rights reserved.