regulation
Last reviewed 03/2021
The triacylglycerol lipase enzyme within adipose tissue is hormone-sensitive and rate-limiting for triglyceride breakdown to fatty acid and diacylglycerol. It exists in two forms; a kinase enzyme activates it from its inactive form; a phosphatase enzyme catalyzes the reverse reaction. The kinase enzyme is activated by agents which raise the concentration of the intracellular secondary messenger, cyclic adenosine monophosphate.
Hence, all of the following agents which raise cAMP are lipolytic:
- adrenaline
- noradrenaline
- glucagon
- ACTH
- TSH
- serotonin
- vasopressin
Anti-lipolytic agents include:
- insulin, by reduction of cyclic adenosine monophosphate
- 3-hydroxybutyrate, by increasing cellular sensitivity to insulin
Growth hormone, glucocorticoids and thyroxine may all be lipolytic by the slower action of new protein formation e.g. to produce enzymes which increase the rapidity of cAMP production.