Inadequate production of insulin or insulin resistance leads to which condition?

• A. Hyperthyroidism
• B. Diabetes mellitus
• C. Cushing's syndrome
• D. Addison's disease

Answer: (B)

Insulin is needed for cells to take up glucose from the blood. When production is inadequate or the body's tissues become resistant to insulin, glucose stays high in the bloodstream, producing diabetes mellitus. This includes type 1, where the pancreas makes little or no insulin, and type 2, where cells are resistant to insulin and production may eventually fall. The other options involve different hormonal problems—hyperthyroidism alters metabolic rate, Cushing's syndrome (excess cortisol) can raise blood sugar but not primarily because of a lack of insulin, and Addison's disease is adrenal insufficiency. So the mechanism described best fits diabetes mellitus.