Hormone-sensitive lipase serves to mediate the hydrolysis of not only triacylglycerol stored in adipose tissue, but also cholesteryl esters in the adrenals, ovaries, testis, and macrophages (Holm , 2003). For those lacking HSL, the breakdown of cellular fat stores fuels energy production and multiple anabolic processes (Zechner and Langin, 2014). HSL is a primary enzyme that mobilizes fatty acids from acylglycerols in adipocytes to non-adipocytes. In adipocytes, catecholamines function for lipolysis primarily through protein kinase. A mediated phosphorylation of HSL and perilipin, a protein covering the lipid droplet. The antilipolytic action of insulin is mainly mediated by lowered camp levels, achieved by activation of phosphodiesterase 3B (Osuga et al., 2000). Say no to plagiarism. Get a tailor-made essay on “Why Violent Video Games Should Not Be Banned”? Get the original essay Next, HSL alone catalyzes the hydrolysis of triglycerides and diglycerides, while the participation of monoglyceride lipase is necessary to achieve complete hydrolysis of monoglycerides. HSL and monoglyceride lipase appear to play a key role in acylglycerol hydrolysis also in non-adipocytes, but the involvement of additional lipases can be anticipated (Holm, 2003). It is encoded by a gene located on chromosome 19 and lacks homology with members of the pancreatic lipase gene family such as lipoprotein lipase (LPL). The lipolytic activities of HSL are under acute neuronal and hormonal control. Catecholamines and other lipolytic hormones stimulate these activities through reversible serine phosphorylation by cyclic adenosine 39,59-monophosphate (cAMP)-dependent protein kinase (PKA). Conversely, insulin, an antilipolytic hormone, suppresses its activities by preventing phosphorylation (Osuga et al., 2000). Therefore, activation of this enzyme in adipose tissue is thought to be responsible for the elevation of plasma free fatty acid (FFA) levels in adipose tissue. various conditions such as starvation or diabetes mellitus. Since mice lacking the b3-adrenergic receptor, a dominant form of b-adrenergic receptor expressed in adipocytes, are obese and mice lacking the RIIb subunit of PKA are lean due to increased activity of the PKA, it is reasonable to assume that HSL is involved in the regulation of adiposity through the adrenergic signaling pathway (Zechner & Langin, 2014). The studies reported below were undertaken with the aim of characterizing and investigating hormone-sensitive lipase activity in adipose tissue without interference from other lipases. By designing appropriate test conditions, I was able to measure lipase activity which apparently reflects rather well the hormone-sensitive lipolytic activity of intact tissue (Vaughan, Berger, and Steinberg, 1964). Keep in mind: this is just a sample. .Get a custom paper now from our expert editors.Get a custom essay The structure and biochemistry of hormone-sensitive lipase is located on chromosome 19q13.3 and was initially described as containing 9 exons spanning approximately 11 and 10 kB in humans and mice, respectively, which encode a 2.8 kB mRNA. Subsequently, two additional exons (designated A and B) that differentially encode 170 and 70 nt 5 untranslated regions were identified approximately 12.5 and 1.5 kB upstream of exon 1, respectively. Only the smaller HSL mRNA product is expressed in human adipose tissue. On the other hand, five different exons were, 2002).