http://www.creativebiomart.net/description_382703_12.htm

Parathyroid hormone (PTH), parathormone or parathyrin, is secreted by the chief cells of the parathyroid glands as a polypeptide. PTH elevates calcium level by dissolving the salts in bone and preventing their renal excretion. PTH may stimulates [1-14C]-2-deoxy-D-glucose (2DG) transport and glycogen synthesis in osteoblastic cells. Parathyroid hormone (PTH) has been proved to play a pivotal role in maintaining myocardial contractility as well as effective natriuresis, and possible pathogenic mechanisms contributing to heart failure secondary to hypocalcemia and hypoparathyroidism. With the increased population of preosteoblastic lineages and the osteoblastic activation, Parathyroid hormone (PTH) drives anabolism in bone. Experiments have recently reported that the absence of osteoclasts in c-fos(- / -) mice might hinder PTH-driven bone anabolism, and that osteoclastic presence may be necessary for full osteoblastic differentiation and enhanced bone formation seen after intermittent PTH administration. Alternatively, it was suggested that PTH administration inhibits sclerostin synthesis by osteocytes, thereby allowing for active bone formation. Taken together, Parathyroid hormone (PTH) affects bone cells in a dual pathway-mediating osteoblastic (preosteoblastic) activities or osteocytic synthesis of sclerostin. Defects in PTH are a cause of familial isolated hypoparathyroidism (FIH), also called autosomal dominant hypoparathyroidism or autosomal dominant hypocalcemia. FIH is characterized by hypocalcemia and hyperphosphatemia due to inadequate secretion of parathyroid hormone.