Characterization of a swelling-activated anion conductance in homozygous typing cell hepatoma cells

Abstract

Liver cell volume and intracellular ion concentrations are maintained within a narrow physiologic range by regulated changes in membrane ion permeability. These studies of homozygous HTC hepatoma cells, a model liver cell line, evaluate the relationship between cell volume and membrane ion permeability, and assess the possibility that cell swelling allows the efflux of the intracellular osmolite taurine through the opening of a conductive pathway. Cell swelling induced by exposure to hypotonic solutions (203 mOsm) caused a rapid increase in cell volume, followed by recovery toward basal values. Volume recovery was inhibited by Cl- depletion or by exposure to the putative Cl- channel blocker 5-nitro-2-(3-phenylpropyl-amino) benzoic acid (NPPB) (25 μmol/L). Swelling increased the efflux rates of 36Cl (181% ± 15%, P < .01) and 125I (310% ± 21%, P