share email twitter ⋅ join discord whatsapp(2ck)
free120  nbme24  nbme23  nbme22  nbme21  nbme20  nbme19  nbme18  nbme17  nbme16  nbme15  nbme13 

NBME 18 Answers

nbme18/Block 3/Question#37 (9.9 difficulty score)
During a clinical study of calcium and ...

Login to comment/vote.

submitted by azibird(158),

Costanzo Physiology 6th E p456

Regulation of Vitamin D Synthesis Whether the renal cells produce 1,25- dihydroxycholecalciferol (the active metabolite) or 24,25-dihydroxycholecalciferol (the inactive metabolite) depends on the “status” of Ca2+ in the body. When Ca2+ is sufficient, with an adequate dietary intake of Ca2+ and normal or increased plasma Ca2+ concentration, the inactive metabolite is preferentially synthesized because there is no need for more Ca2+. When Ca2+ is insufficient, with a low dietary intake of Ca2+ and decreased plasma Ca2+ concentration, the active metabolite is preferentially synthesized to ensure that additional Ca2+ will be absorbed from the gastrointestinal tract.

cbreland  Constanzo is the best resource, change my mind +