<prompt> PTH does what directly?Controls the rate of 25-hydroxycholicalciferol formationControls the rate of calcium transpo in the mucosa of the small intestineControls the rate of formation of calcium-binding proteinControls the rate of formation of 1,25-dihydroxycholicalciferol  <response>: 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 