What is the mechanism of action of lipolysis?

Lipolysis breaks down triglycerides into free fatty acids and glycerol through a specific enzymatic process.

Here's a detailed look at the mechanism:

Lipolysis Explained

Lipolysis is the metabolic pathway that hydrolyzes triglycerides (TGs) into glycerol and three fatty acids. This process primarily occurs in adipocytes (fat cells) and is crucial for providing energy during fasting or exercise.

Enzymatic Steps of Lipolysis

Lipolysis involves the sequential action of three key enzymes:

1. Adipose Triglyceride Lipase (ATGL):

   • ATGL is the initial enzyme that starts the breakdown of triglycerides.
   • It catalyzes the hydrolysis of triglyceride to diacylglycerol (DAG).

2. Hormone-Sensitive Lipase (HSL):

   • HSL acts on diacylglycerol (DAG), hydrolyzing it to monoacylglycerol (MAG).
   • The activity of HSL is tightly regulated by hormones like insulin and catecholamines.

3. Monoglyceride Lipase (MGL):

   • MGL completes the lipolysis process by hydrolyzing monoacylglycerol (MAG) into glycerol and a free fatty acid.

Hormonal Regulation

The lipolytic pathway is tightly regulated by hormones. For instance, catecholamines (e.g., epinephrine) stimulate lipolysis, while insulin inhibits it.