rhuPTH - rekombinantes humanes Parathyroidhormon (aa 1-34)

Parathyroid hormone (PTH), or parathormone, is secreted by the parathyroid glands as a polypeptide of 84 amino acids. It acts to increase the concentration of calciumin in the blood, whereas calcitonin (a hormone produced by the parafollicular cells of the thyroid gland) acts to decrease calcium concentration. PTH acts to increase the concentration of calcium in the blood by acting upon parathyroid hormone receptor in three parts of the body: In the bones it enhances the release of calcium from the large reservoir contained in the bones. Bone resorption is the normal destruction of bone by osteoclasts, which are indirectly stimulated by PTH. Stimulation is indirect since osteoclasts do not have a receptor for PTH; rather, PTH binds to osteoblasts, the cells responsible for creating bone. Binding stimulates osteoblasts to increase their expression of RANKL, which can bind to osteoclast precursors containing RANK, a receptor for RANKL. The binding of RANKL to RANK stimulates these precursors to fuse, forming new osteoclasts which ultimately enhances the resorption of bone.
In the kidney it enhances active reabsorption of calcium from distal tubules and the thick ascending limb.
In the intestine it enhances the absorption of calcium by increasing the production of vitamin D and upregulating the enzyme responsible for 1-alpha hydroxylationof 25-hydroxy vitamin D, converting vitamin D to its active form (1,25-dihydroxy vitamin D) which effects the actual absorption of calcium (as Ca2+ ions) by the intestine via calbindin.

Recombinant human full length PTH 1-84 has potential as an anti-osteoporotic agent, due to its properties as a bone formation stimulant, it increases bone turnover, stimulating osteoblasts and reducing both vertebral and non vertebral fractures.

Rekombinantes humanes Parathyroidhormon (C181H290N55O51S2) wird in E.Coli als ein nichtglycosyliertes Polypeptid von 34 Aminosäuren und einer Molmasse von 4117.8 Dalton exprimiert.

Synonyme: Parathyrin, PTH, Parathormon.