PTH regulates calcium levels in the blood through three primary mechanisms: 1. Bone Resorption: PTH stimulates the release of calcium from bones into the bloodstream. 2. Renal Reabsorption: It enhances the kidneys' ability to reabsorb calcium, reducing urinary calcium loss. 3. Intestinal Absorption: PTH indirectly increases calcium absorption in the intestines by stimulating the production of active vitamin D.
