Excess of which hormone causes hyperglycemia by promoting gluconeogenesis and glycogenolysis?

• A. Corticosteroid
• B. Insulin
• C. Growth hormone
• D. Thyroid hormone

Answer: (A)

Excess corticosteroids raise blood sugar by turning up the liver’s glucose production and promoting glycogen breakdown. Glucocorticoids like cortisol increase the expression of gluconeogenic enzymes (for example, PEPCK and glucose-6-phosphatase) in the liver, boosting hepatic glucose output. They also stimulate glycogenolysis, releasing more glucose from stored glycogen. Additionally, they antagonize insulin, reducing glucose uptake in muscle and fat and contributing to insulin resistance. While other hormones can influence glucose levels, this combination of enhanced gluconeogenesis and glycogenolysis driven by high corticosteroid levels is the classic cause of hyperglycemia.