title: 1,25-Dihydroxyvitamin D3 stimulates Ca-ATPase in a vascular smooth muscle cell line.
abstract: I have recently shown that a vascular smooth muscle cell line has receptors for 1,25-dihydroxyvitamin D. To examine a possible role of 1,25-dihydroxyvitamin D in the regulation of cellular calcium homeostasis, effect of the sterol on Ca-ATPase activity was studied. 1,25-dihydroxyvitamin D3 stimulated the enzyme activity in a dose dependent manner at 10(-10) and 10(-9) M when the cells were incubated with the sterol for 10 hours. By contrast, 60 minutes incubation of the cells with 1,25-dihydroxyvitamin D failed to stimulate the enzyme activity. Both 25-dihydroxyvitamin D3 and 24,25-dihydroxyvitamin D3 did stimulate the enzyme activity, but at three orders of magnitude higher concentrations. Cycloheximide, at 10(-5)M, abolished the action of 1,25-dihydroxyvitamin D3. These data suggest that 1,25-dihydroxyvitamin D3 stimulates Ca-ATPase activity probably via its receptor and may play a role in regulating cellular calcium homeostasis.
mesh_terms: D015650:24,25-Dihydroxyvitamin D 3; D000818:Animals; D001011:Aorta; D002112:Calcifediol / Q000494:pharmacology; D002117:Calcitriol / Q000494:pharmacology*; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D002460:Cell Line; D003513:Cycloheximide / Q000494:pharmacology; D004100:Dihydroxycholecalciferols / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004622:Embryo, Mammalian; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000201:enzymology*; D051381:Rats
chemical_list: D004100:Dihydroxycholecalciferols; D015650:24,25-Dihydroxyvitamin D 3; D003513:Cycloheximide; D000252:Calcium-Transporting ATPases; D002117:Calcitriol; D002112:Calcifediol