Rapid, non-genomic actions of progesterone and estradiol on steady-state calcium and resting calcium influx in lens epithelial cells

Document Type

Article

Publication Title

Pflugers Archiv European Journal of Physiology

Abstract

The effects of steroids on the steady-state intracellular [Ca2+] ([Ca2+]i) and resting Ca2+ influx in Fura-2-loaded bovine lens epithelial cells were examined to identify potential rapid, non-genomic actions. When administered in the presence of 1-2 mM extracellular Ca2+ ([Ca2+]o), 100 μM progesterone produced large (up to 12-fold) and transient (5 min) increases in [Ca2+]i. These effects were abolished in EGTA-containing solutions, and were associated with large increases in the rate at which extracellularly administered Mn2+ quenched the intracellular Fura signal. Lower concentrations of progesterone (10-100 μM) produced smaller increases in [Ca2+]i that were concentration dependent, and 17β-estradiol induced large, rapid and brief increases in [Ca2+]i at 100 nM and smaller oscillations in [Ca2+]i at 10 nM. In cells pretreated with thapsigargin, 100 μM progesterone produced slower increases in [Ca2+]i that were maintained for several minutes. These results demonstrate rapid non-genomic actions of progesterone and estradiol on resting Ca2+ influx and [Ca2+]i that may involve specific interactions with a recently discovered steroid-binding protein in the plasma membrane of lens epithelial cells.

First Page

700

Last Page

709

DOI

10.1007/s00424-002-0889-7

Publication Date

9-1-2002

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