HOW DO PTH AND CALCITRIOL WORK TOGETHER NORMALLY?
Parathyroid hormone (PTH) and calcitriol comprise the team of polypeptide and steroid hormones responsible for maintaining adequate levels of blood calcium. When blood calcium falls, PTH secretion is stimulated. PTH increases synthesis of calcitriol. Calcitriol increases calcium absorption in the intestine. In bone, calcitriol causes formation of increased numbers of osteoclasts. The activation of bone resorption brought about by PTH is markedly facilitated by these increased numbers of osteoclasts.
