AJP - Renal Physiology, Vol 251, Issue 2 188-F198, Copyright © 1986 by American Physiological Society
Effects of parathyroid hormone on cytosolic calcium in renal proximal tubular primary cultures
K. A. Hruska, M. Goligorsky, J. Scoble, M. Tsutsumi, S. Westbrook and D. Moskowitz
The effects of parathyroid hormone on the cytoplasmic Ca2+ concentration of
canine renal proximal tubule cells grown in primary culture were determined
using the fluorescent Ca2+ indicator quin 2. The cultured cells exhibited
responses to hormones, enzyme activities, transport functions, and
morphology characteristic of the proximal convoluted tubule. Parathyroid
hormone stimulated an immediate rise in cytoplasmic Ca2+, both in suspended
cells and cells studied as a monolayer on Nuclepore filters. The rise in
cytoplasmic Ca2+ induced by the hormone was sustained for 15-30 min, was
dose dependent, and was not mimicked by cyclic AMP. Removing Ca2+ from the
extracellular media markedly decreased cytoplasmic Ca2+ and abolished the
effects of parathyroid hormone on cytosolic Ca2+.
8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate blocked the effects of
the hormone on cytosolic Ca2+, but mitochondrial uncouplers failed to
inhibit the effects of the hormone to increase cytoplasmic Ca2+. These
studies support a role of Ca2+ in the activation of proximal renal tubule
cells by parathyroid hormone.
