**Question:** An oral hypoglycemic agent used to treat obesity is: September 2008

**Core Concept:** Oral hypoglycemic agents are medications used to control blood sugar levels in patients with diabetes mellitus. In the context of obesity treatment, we are specifically discussing agents that have an additional effect beyond their primary role as antidiabetic drugs.

**Why the Correct Answer is Right:** The correct answer, D-Methionyl-Leptin, is a form of Leptin, a hormone produced by adipose tissue that regulates appetite, energy expenditure, and body weight. Leptin helps in controlling hunger and satiety signals to the brain. Methionyl-Leptin is an analogue of Leptin that has been developed for oral administration, making it suitable for use as an oral hypoglycemic agent.

**Why Each Wrong Option is Incorrect:**

A. Glipizide (a sulfonylurea): Glipizide is an antidiabetic drug that works by stimulating insulin release from the pancreas, but does not directly address obesity.

B. Orlistat (an inhibitor of lipase): Orlistat is a medication that inhibits gastric and pancreatic lipase, preventing the absorption of fat in the GI tract. While it may contribute to weight loss, it is primarily an antiobesity drug, not an oral hypoglycemic agent.

C. Gemfibrozil (a fibrate): Gemfibrozil is a lipid-lowering agent that works by reducing triglyceride production in the liver and increasing HDL cholesterol levels. It does not specifically target obesity or blood glucose control.

**Clinical Pearl:** Methionyl-Leptin, as a form of Leptin, is an interesting development in obesity management. However, it is essential to understand that this medication is primarily developed for its effect on blood glucose control, making it an oral hypoglycemic agent. While it may have some impact on obesity, its primary purpose is not to directly address obesity, unlike the other options provided.

**Correct Answer:** D-Methionyl-Leptin is the correct answer as it is an oral hypoglycemic agent, specifically designed to control blood glucose levels. It is a form of Leptin that can be administered orally, unlike the other options provided that are not specifically designed for blood glucose control.