Which of the following is not a function of insulin
**Core Concept**
Insulin is a hormone secreted by the beta cells of the pancreas, playing a crucial role in glucose metabolism. It facilitates the uptake of glucose by cells, inhibits gluconeogenesis and glycogenolysis, and promotes glycogen synthesis.
**Why the Correct Answer is Right**
Insulin regulates various cellular processes by binding to its receptor on the cell surface, triggering a cascade of intracellular signaling pathways. These pathways ultimately lead to the translocation of glucose transporter type 4 (GLUT4) to the cell surface, facilitating glucose uptake. Insulin also inhibits the activity of key enzymes involved in gluconeogenesis and glycogenolysis. However, one of the key functions of insulin is not listed among the options.
**Why Each Wrong Option is Incorrect**
**Option A:** is incorrect because insulin indeed promotes the uptake of glucose by cells, inhibits gluconeogenesis, and facilitates glycogen synthesis.
**Option B:** is incorrect because insulin promotes the synthesis of glycogen in the liver and muscles.
**Option C:** is incorrect because insulin inhibits glycogenolysis in the liver and muscles, preventing the breakdown of glycogen to glucose.
**Clinical Pearl / High-Yield Fact**
Insulin resistance is a key feature of type 2 diabetes, where the body's cells become less responsive to insulin, leading to elevated blood glucose levels.
**Correct Answer: D.**