Parathyroid hormone ?
Correct Answer: Increases bone resorption
Description: Ans. is 'b' i.e., Increases bone resorptionParatharmoneParatharmone is 84 aminoacid polypeptide hormone secreted from parathyroid glands.Its secretion is regulated by plasma Ca++ concentration -- fall in Ca++ concentration increases the secretion of paratharmone.ActionsPTH increases resorption of calcium from bone - most prominant action.PTH increases calcium reabsorption from distal tubules of kidney.PTH decreases phophate reabsorption from proximal tubules of kidney.PTH has no direct effect on calcium absorption from intestine but increases it indirectly by enhancing the formation of calcitriol by activating loc-hydroxylose.PTH decreases calcium level in milk, saliva, and ocular lens -- may be responsible for development of cataract in hypothyroidism.Drugs related to paratharmone CinacalcentIt activates the Ca++ sensing receptor (CaR) in parathyroid glands and blocks PTH secretion.It is indicated in secondary hyperparathyroidism due to renal disease and in parathyroid tumor.TeriparatideThis is recombinant preparation of 1-34 residues of amino terminal of human PTH.It is used in osteoporosis.The effect is faster and more marked than that produced by estrogen and bisphosphonates.Teriparatide in the only agent which stimulates bone formation whereas estrogen and biphosphonate only check bone resorption.
Category:
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