1 alpha,25(OH)2 vitamin D3-mediated stimulation of outward anionic currents in osteoblast-like ROS 17/2.8 cells.
1 alpha,25-dihydroxyvitamin-D3 [1 alpha,25(OH)2D3] is known to potentiate in osteoblast-like rat osteosarcoma cells (ROS 17/2.8) the influx of Ca2+ through voltage-activated L-type Ca2+ channels. In the present study, by means of the whole-cell patch-clamp technique, we found that physiological concentrations of 1 alpha,25(OH)2D3 (5-5000 x 10(-11) M) also stimulate, in a dose-dependent manner, outwardly rectifying anionic currents over the course of 1-5 minutes. These currents, recorded in the presence of 130 mM glutamate or approximately 140 mM C1- in the external solution, were blocked by 200 microM DIDS, a stilbene derivative selective for C1- channels. We conclude that, in addition to the already known effects of 1 alpha,25(OH)2D3 on Ca2+ channels, the hormone also enhances in ROS 17/2.8 cells an outward anion conductance. This is the first report concerning activation of anion channels by 1 alpha,25(OH)2D3.
Zanello
L P
LP
Department of Biochemistry, University of California, Riverside 92521, USA.
Norman
A W
AW
D000818:Animals; D002117:Calcitriol / Q000494:pharmacology*; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D018118:Chloride Channels / Q000187:drug effects* / Q000502:physiology; D015640:Ion Channel Gating; D008564:Membrane Potentials; D010006:Osteoblasts / Q000166:cytology / Q000502:physiology*; D051381:Rats
D015220:Calcium Channels; D018118:Chloride Channels; D002117:Calcitriol