Single cell analysis of changes in cytosolic calcium induced by vitamin D3 metabolites in cultured rat mesangial cells.
The acute effects of 1,25-Dihydroxy-vitamin D3 [1,25(OH)2D3] on the concentration of cytoplasmic ionized calcium [Ca2+] of cultured rat mesangial cells were studied at the single cell level by microspectrofluorometry of fura-2-loaded cells. Addition of 1,25(OH)2D3 produced an immediate increase of [Ca2]+. This rise in [Ca2+] was sustained and similar to that caused by the Ca2+ channel agonist BAY K 8644. Comparable changes were also observed in cultured human mesangial cells. The effects of the hormone (10 (-10)-10(-7) M) were dose-dependent (62% and 285%). Only 30-40% of the cells responded to stimulation with 1,25(OH)2D3. 25OHD3 also increased Ca2+ whereas 24,25(OH)2D3 and 1aOHD3 were inactive. Addition of 1 mM CoCl2 or 2-5 microM nifedipine largely blocked the effects of 1,25(OH)2D3 suggesting the involvement of Ca2+ channel activation in the rapid 1,25(OH)2D3-induced increase in mesangial cell [Ca2+]. 45Ca uptake studies are consistent with This interpretation.
Boland
R L
RL
Departamento de Biologia, Universidad Nacional del Sur. Bahia Blanca, Argentina.
de Boland
A R
AR
Nobiling
R
R
Weinreich
T
T
Ritz
E
E
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000818:Animals; D002112:Calcifediol / Q000494:pharmacology*; D002117:Calcitriol / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005920:Glomerular Mesangium / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D009543:Nifedipine / Q000494:pharmacology; D051381:Rats
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D002117:Calcitriol; D009543:Nifedipine; D002112:Calcifediol; D002118:Calcium