PTH does what directly?: (A) Controls the rate of 25-hydroxycholicalciferol formation, (B) Controls the rate of calcium transpo in the mucosa of the small intestine, (C) Controls the rate of formation of calcium-binding protein, (D) Controls the rate of formation of 1,25-dihydroxycholicalciferol
Answer is D. Parathyroid hormone acts in the renal coex to stimulate the reaction forming 1,25-dihydroxycholicalciferol from 25-hydroxycholicalciferol. It has no effects on other the other reactions