True statement regarding insulin
**Core Concept**
Insulin is a hormone produced by the beta cells of the pancreatic islets, playing a crucial role in glucose metabolism by facilitating glucose uptake in cells, thereby reducing blood glucose levels.
**Why the Correct Answer is Right**
Insulin acts by binding to its receptor on the surface of target cells, triggering a cascade of intracellular signaling pathways that ultimately lead to the translocation of glucose transporter type 4 (GLUT4) to the cell surface. This increases the uptake of glucose into the cell, which in turn reduces blood glucose levels. Insulin also has a role in lipid and protein metabolism, inhibiting lipolysis and protein degradation.
**Why Each Wrong Option is Incorrect**
**Option A:** This option might be incorrect if it contradicts the established mechanism of insulin action or suggests an unrelated function of insulin.
**Option B:** This option might be incorrect if it implies insulin has a direct effect on glycogenolysis, when in fact, insulin inhibits glycogen breakdown but stimulates glycogen synthesis.
**Option C:** This option might be incorrect if it suggests insulin has a role in increasing gluconeogenesis, when in fact, insulin inhibits gluconeogenesis in the liver.
**Clinical Pearl / High-Yield Fact**
Insulin resistance, a condition where cells become less responsive to insulin, is a hallmark of type 2 diabetes mellitus. This can be due to various factors, including genetic predisposition, obesity, and physical inactivity.
**Correct Answer:** None provided. Please provide the options for a complete explanation.