Hormone sensitive lipase/HSL Recombinant Rabbit mAb (S-5482)

Hormone-sensitive lipase (HSL) is an intracellular neutral lipase that was long regarded as the rate-limiting enzyme for triglyceride hydrolysis in adipose tissue; it is now known to act primarily at the diacylglycerol step of the lipolytic cascade, hydrolyzing diacylglycerol to monoacylglycerol. HSL activity is acutely regulated by reversible phosphorylation: catecholamines and other hormones phosphorylate HSL via the cAMP/PKA pathway, promoting its translocation to lipid droplets where it exerts its hydrolytic action, whereas insulin inhibits this process. The enzyme has an unusually broad substrate specificity, hydrolyzing not only triglycerides, diacylglycerols, and monoacylglycerols but also cholesterol esters, steroid fatty acid esters, and retinyl esters. HSL is highly expressed in adipose tissue and steroidogenic tissues, and is also expressed in cardiac muscle, skeletal muscle, macrophages, and pancreatic islets; in steroidogenic tissues it is mainly responsible for converting cholesterol esters into free cholesterol for hormone synthesis. At the pathophysiological level, HSL expression and activity correlate significantly with the maximal lipolytic capacity of human adipocytes, and abnormalities in its activity are involved in obesity, insulin resistance, and the excessive release of free fatty acids in diabetic ketoacidosis.