Which hormones counterregulate hypoglycemia and promote glucose release during fasting?

• A. Glucagon and epinephrine (with cortisol and growth hormone contributing)
• B. Insulin and amylin
• C. Thyroid hormone and cortisol
• D. Cortisol alone

Answer: (A)

During fasting, the body uses counterregulatory hormones to oppose insulin and push glucose back into the bloodstream. The fastest and most important are glucagon and epinephrine. Glucagon acts on the liver to break down glycogen (glycogenolysis) and to make new glucose (gluconeogenesis), raising blood glucose quickly. Epinephrine supports this by promoting glycogen breakdown and stimulating gluconeogenesis, and it also helps mobilize fatty acids to spare glucose for essential organs. Cortisol and growth hormone contribute as well, especially during longer fasts, by sustaining gluconeogenesis and limiting peripheral glucose use, but they are slower and less immediate than glucagon and epinephrine. So the combination of glucagon and epinephrine best accounts for rapid glucose release during fasting, with cortisol and growth hormone providing additional support.