A Ca2+ channel in renal epithelial cells introduced by parathyroid hormone
Suzuki, M.; Taniguchi, J.
Mineral and Electrolyte Metabolism 21(1-3): 35-39
1995
ISSN/ISBN: 0378-0392 PMID: 7565459 Document Number: 442772
To investigate the mechanism of Ca-2+ influx after hormonal stimuli, patch clamping with (Ca-2+)-i fluorescence measurement was performed in single renal proximal epithelial cells. A Ca-2+ current appeared along with a rise in (Ca-2+)-i during parathyroid hormone addition to the bath, but not when the hormone was inside the cell-attached pipette. The Ca-2+ channel, possessing linear I-V, was nonselective for cations, most active in hyperpolarized - membranes and showed oscillatory fluctuations in opening, which disappeared after excision. GTP-gamma-S opened the channel that had disappeared, which was suppressed by GDP-beta-S. These data show a PTH-responsive Ca-2+ channel for which GTP/GDP may act as second messenger to open the latent Ca-2+ channel.