HSL (hormone-sensitive lipase), a cytosolic neutral lipase regulated by reversible phosphorylation, catalyzes the rate limiting step in triglyceride lipolysis. Lipolytic stimuli activate adenylyl cyclase and thus increase intracellular cAMP levels, which in turn activate protein kinase A (PKA). HSL has been shown to express in several non-adipose tissues, including ovary, adrenal gland, heart, skeletal and smooth muscle, placenta, and pancreatic beta-cells, as well as testes. HSL has emerged as a potential target for lipid disorders and obesity.