Calcium Homeostasis: Physiological Regulation by Parathyroid Hormone and Vitamin D

Abstract

Calcium homeostasis is essential for the maintenance of numerous physiological processes, including neuromuscular function, bone remodeling, enzymatic activity, and blood coagulation. The human body regulates serum calcium levels within a narrow range through an intricate feedback system primarily involving the parathyroid hormone (PTH), vitamin D, and to a lesser extent, calcitonin. This review outlines the physiological mechanisms through which PTH and vitamin D maintain calcium balance, emphasizing their synergistic roles in intestinal absorption, renal reabsorption, and skeletal mobilization of calcium.