parathyroid hormone

Last reviewed 01/2018

  • parathyroid hormone is an 84 amino acid peptide produced by the parathyroid glands. Release is stimulated when there is a fall in serum calcium concentration. Physiological activity is confined to the first 34 residues of the N-terminal end. Indeed, hepatic splicing of this fragment may make it more active

  • parathyroid hormone promotes phosphate excretion in the kidney by restricting tubular reabsorption and conserves calcium by increasing reabsorption. It also stimulates an increase in osteoclastic activity in bone and hence bone resorption, which also results in a raised serum calcium. A rise in the level of PTH, or a fall in phosphate, increases the renal production of the active form of vitamin D - 1,25-dihydroxycholelcalciferol - and hence an increased intestinal absorption of calcium. Therefore the overall effect of PTH secetion is increased calcium and reduced phosphate in the plasma

  • synthesis - parathyroid hormone is produced in the chief cells of the parathyroid glands. It is synthesized on a continuous basis; there is no storage