Alteration of gastric surface cell pH regulation by sodium taurocholate

Gastric mucosal cells from guinea pigs were grown in cell culture. Acridine orange fluorescence at 624 nm was used as an qualitative indicator of intracellular pH. The cultured cells were exposed to Hank's solution at pH 7.4, 6.0, 5.0, 4.0, 3.0, and 1.8 for 30 min. After removal of the acid, the cells were loaded with acridine orange for qualitative pH assessment. The cells developed alkaline shifts in the cytoplasmic pH in direct proportion to the acid load. This alkaline overcorrection after exposure to acid was blocked by amiloride and blunted by taurocholic acid in a dose-dependent fashion. These results suggest that gastric surface cells may regulate their cytoplasmic pH with a sodium-hydrogen antiporter. These results also suggest that this antiport system may be adversely affected by bile salts.