parathyroid hormone (7-34) [Homo sapiens] [Macaca fascicularis], (C154H246N48O40S2),a peptide with the sequence H2N-LMHNLGKHLNSMERVEWLRKKLQDVHNF-OH, MW= 3474.03. Parathyroid hormone (PTH), parathormone or parathyrin, is secreted by the chief cells of the parathyroid glands as a polypeptide containing 84 amino acids. It acts to increase the concentration of calcium (Ca2+) in the blood, PTH acts to increase the concentration of calcium in the blood by acting upon the parathyroid hormone 1 receptor and the parathyroid hormone 2 receptor(1). PTH reduces the reabsorption of phosphate from the proximal tubule of the kidney,[8] which means more phosphate is excreted through the urine. PTH enhances the uptake of phosphate from the intestine and bones into the blood(2). In the bone, slightly more calcium than phosphate is released from the breakdown of bone. In the intestines, absorption of both Calcium and Phosphate is mediated by an increase in activated vitamin D.
References:
1. Bieglmayer C, Prager G, Niederle B (October 2002). "Kinetic analyses of parathyroid hormone clearance as measured by three rapid immunoassays during parathyroidectomy". Clin. Chem. 48 (10): 1731-8.
2. PooleK, Reeve J (2005). "Parathyroid hormone - a bone anabolic and catabolic agent". Curr Opin Pharmacol 5 (6): 612-7.