Parathyroid hormone primarily influences the metabolism of which minerals?

• A. Sodium and potassium
• B. Magnesium and phosphate
• C. Iron and zinc
• D. Calcium and phosphorus

Answer: (D)

Parathyroid hormone primarily governs calcium and phosphorus metabolism. It raises blood calcium by stimulating calcium release from bone, increasing calcium reabsorption in the kidneys, and promoting the production of active vitamin D (calcitriol) to boost intestinal calcium absorption. It also lowers blood phosphate by reducing renal phosphate reabsorption, causing more phosphate to be excreted in urine. Because of these actions, calcium and phosphorus are the minerals most affected by PTH. Sodium and potassium are regulated mainly by other hormones and mechanisms, and iron and zinc are controlled by different processes related to storage, transport, and absorption. So the minerals most influenced by parathyroid hormone are calcium and phosphorus.