1,25-Dihydroxyvitamin D and not calcium is the major regulator of calbindin-D 9-kDa mRNA levels in vivo.
A possible role of calcium in vivo on intestinal calbindin-D 9-kDa mRNA levels has been studied in rats. In vitamin D-deficient rats, a marked increase in dietary calcium has a small but significant effect on calbindin-D 9-kDa mRNA levels, despite a dramatic increase in serum calcium concentration that clearly resulted from increased intestinal absorption of calcium. On the other hand, vitamin D under all circumstances increased calbindin-D 9-kDa mRNA levels, with the greatest levels found in animals on a low calcium diet where little or no calcium is available for absorption. These results strongly support the idea that 1,25-dihydroxyvitamin D is directly responsible for the induction of calbindin-D 9-kDa.
Strom
M
M
Department of Biochemistry, University of Wisconsin-Madison, College of Agricultural and Life Sciences 53706.
Krisinger
J
J
Darwish
H
H
DeLuca
H F
HF
D000818:Animals; D064026:Calbindins; D002117:Calcitriol / Q000502:physiology*; D002118:Calcium / Q000502:physiology*; D008297:Male; D012333:RNA, Messenger / Q000032:analysis*; D051381:Rats; D011919:Rats, Inbred Strains; D064030:S100 Calcium Binding Protein G / Q000235:genetics*
D064026:Calbindins; D012333:RNA, Messenger; D064030:S100 Calcium Binding Protein G; D002117:Calcitriol; D002118:Calcium