Identify the primary enzyme responsible for initiating the mobilization of stored triglycerides from adipose tissue for subsequent fatty acid oxidation.

The primary enzyme responsible for initiating the mobilization of stored triglycerides from adipose tissue for subsequent fatty acid oxidation is Hormone-Sensitive Lipase (HSL). Adipose tissue, consisting mainly of adipocytes (fat cells), is the body's primary site for storing triglycerides, which are the main form of stored energy. HSL catalyzes the breakdown, or hydrolysis, of these stored triglycerides into fatty acids and glycerol. While Adipose Triglyceride Lipase (ATGL) initiates the first step by cleaving one fatty acid from a triglyceride, HSL is the key rate-limiting enzyme that acts primarily on diacylglycerols (diglycerides) and monoacylglycerols (monoglycerides) to release the remaining fatty acids. Its activity is highly regulated by hormones such as epinephrine and glucagon, which signal a need for energy by activating HSL through phosphorylation, thus initiating the rapid mobilization of fatty acids from fat stores. Once released, the fatty acids are transported in the bloodstream to other tissues, like muscle, where they undergo beta-oxidation, a metabolic process that breaks down fatty acids to generate adenosine triphosphate (ATP), the body's primary energy currency. The glycerol released during triglyceride hydrolysis is transported to the liver, where it can be used for gluconeogenesis, the synthesis of new glucose.