Which statement accurately describes the pathophysiology of Cushing's disease?

Which statement accurately describes the pathophysiology of Cushing's disease?

• A. Cushing's disease is characterized by an oversecretion of insulin.
• B. Cushing's disease is characterized by an oversecretion of glucocorticoid hormones.
• C. Cushing's disease is characterized by an undersecretion of corticotropic hormones.
• D. Cushing's disease is characterized by an undersecretion of glucocorticoid hormones.

Answer: (B)

The main concept here is that Cushing's disease causes excess glucocorticoids due to a pituitary tumor. A pituitary adenoma secretes excessive ACTH, which stimulates the adrenal cortex to overproduce cortisol, the main glucocorticoid. This results in hypercortisolism with the accompanying metabolic and systemic effects. The pituitary source keeps ACTH high even when cortisol rises, because the tumor disrupts the normal negative feedback. So the hallmark is oversecretion of glucocorticoid hormones. Overproduction of insulin isn’t the driving factor, and undersecretion of ACTH or glucocorticoids would lead to opposite problems rather than Cushing’s.

The main concept here is that Cushing's disease causes excess glucocorticoids due to a pituitary tumor. A pituitary adenoma secretes excessive ACTH, which stimulates the adrenal cortex to overproduce cortisol, the main glucocorticoid. This results in hypercortisolism with the accompanying metabolic and systemic effects. The pituitary source keeps ACTH high even when cortisol rises, because the tumor disrupts the normal negative feedback. So the hallmark is oversecretion of glucocorticoid hormones. Overproduction of insulin isn’t the driving factor, and undersecretion of ACTH or glucocorticoids would lead to opposite problems rather than Cushing’s.