Lipolysis
（重定向自Adipolysis）
![Illustration of the process of lipolysis (in a fat cell) induced by high epinephrine and low insulin levels in the blood. Epinephrine binds to a beta-adrenergic receptor in the cell wall of the adipocyte, which causes cAMP to be generated inside the cell. The cAMP activates a protein kinase, which phosphorylates and thus, in turn, activates a hormone-sensitive lipase in the fat cell. This lipase cleaves free fatty acids from their attachment to glycerol in the fat stored in the fat droplet of the adipocyte. The free fatty acids and glycerol are then released into the blood. Monoglycerides are hydrolyzed by monoglyceride lipase.[1]The activity of hormone sensitive lipase is regulated by the circulation hormones insulin, glucagon, norepinephrine, and epinephrine, as shown in the diagram.](/uploads/202412/20/Metabolism11623.jpg)
Lipolysis /lᵻˈpɒlᵻsɪs/ is the breakdown of lipids and involves hydrolysis of triglycerides into glycerol and free fatty acids. The following hormones induce lipolysis: epinephrine, norepinephrine, ghrelin, growth hormone, testosterone, and cortisol. These trigger 7TM receptors (G protein-coupled receptors), which activate adenylate cyclase. This results in increased production of cAMP, which activates protein kinase A, which subsequently activates lipases found in adipose tissue.