Which hormone is a counterregulatory hormone that opposes insulin action?

• A. Insulin
• B. Glucose
• C. Cortisol
• D. Leptin

Answer: (C)

Counterregulatory hormones oppose insulin to raise blood glucose when it’s needed. Cortisol fits this role by stimulating hepatic gluconeogenesis and glycogenolysis, and by reducing glucose uptake in peripheral tissues, which together raise blood sugar and counter insulin’s effects. This helps maintain energy supply during stress or fasting. Insulin lowers blood glucose by promoting uptake and storage; glucose is a substrate, not a hormone; leptin mainly regulates appetite and energy balance and doesn’t directly counteract insulin’s glucose-lowering actions.