Ketoconazole activates chloride and fluid secretion by Necturus gallbladder at low pH

Necturus gallbladder epithelium, normally a reabsorptive epithelium, was stimulated to secrete chloride and fluid by the combined effects of ketoconazole and a reduction in perfusate pH to 7.0. The reversal in the direction of net fluid transport was accompanied by inhibition of the conductance of the apical cell membrane to sodium, potassium, and a striking stimulation of the conductance to chloride. The results are consistent with a previously unidentified mechanism for regulation of the apical cell membrane transport properties of reabsorptive epithelia.