gen-define-the-role-of-insulin-in-metabolism-and-give-one-short-ba0a

Define the role of insulin in metabolism and give one short worked example.

# Role of Insulin in Metabolism ## Definition Insulin is an anabolic hormone produced by pancreatic β-cells that regulates glucose homeostasis and promotes energy storage. ## Key Metabolic Roles 1. **Glucose metabolism** - Increases cellular glucose uptake (muscle, adipose tissue) - Stimulates glycogen synthesis (glycogenesis) - Inhibits glucose production (gluconeogenesis) 2. **Lipid metabolism** - Promotes fat storage (lipogenesis) - Inhibits fat breakdown (lipolysis) 3. **Protein metabolism** - Stimulates protein synthesis - Inhibits protein degradation --- ## Worked Example **Scenario:** A healthy person eats a meal containing 75g of carbohydrates. **Response:** 1. **Blood glucose rises** from 5 mM to ~8 mM (30 min post-meal) 2. **Pancreas secretes insulin** (~50-100 μU/mL baseline → 200-300 μU/mL) 3. **Insulin actions:** - GLUT4 transporters move to cell membranes → muscle/fat cells take up glucose - Liver activates glycogen synthase → stores ~30g as glycogen - Remaining glucose used for immediate energy or converted to fat 4. **Result:** Blood glucose returns to normal (~5 mM) within 2-3 hours **Without insulin (Type 1 Diabetes):** Glucose remains elevated (>10 mM), leading to hyperglycemia and glucose spillage into urine.