**Core Concept**
The storage triacylglycerol in adipocytes (fat cells) are hydrolyzed by specific enzymes that play crucial roles in regulating fat metabolism. This process involves the breakdown of triacylglycerol into glycerol and free fatty acids, which can then be released into the bloodstream or utilized within the cell.

**Why the Correct Answer is Right**
Hormone-sensitive lipase (HSL) is a key enzyme responsible for the hydrolysis of storage triacylglycerol in adipocytes. HSL is activated by hormones such as epinephrine and norepinephrine, which stimulate the breakdown of fat stores to provide energy. This process is essential for regulating energy homeostasis and responding to changes in nutritional status. HSL acts on the triacylglycerol stored within adipocytes, breaking it down into glycerol and free fatty acids.

**Why Each Wrong Option is Incorrect**
**Option A:** Pancreatic lipase primarily acts on dietary triglycerides in the small intestine, breaking them down into monoglycerides and free fatty acids for absorption. It is not involved in the hydrolysis of stored triacylglycerol in adipocytes.
**Option B:** Lipoprotein lipase is involved in the breakdown of triglycerides within lipoproteins, such as VLDL and chylomicrons, in the capillaries of muscle and adipose tissue. While it does play a role in lipid metabolism, it is not the primary enzyme responsible for hydrolyzing stored triacylglycerol in adipocytes.
**Option C:** Lysosomal lipase is involved in the breakdown of lipids within lysosomes, primarily in the context of lipid storage diseases such as Wolman disease. It is not the primary enzyme responsible for hydrolyzing stored triacylglycerol in adipocytes.

**Clinical Pearl / High-Yield Fact**
Hormone-sensitive lipase is a key regulator of fat metabolism and is activated by epinephrine and norepinephrine, which are released in response to stress, exercise, and other stimuli. This knowledge can be applied clinically to understand the mechanisms underlying weight loss and metabolic disorders.

**✓ Correct Answer:** D. Hormone sensitive lipase