Effect of Cycloheximide on Unidirectional Sodium Fluxes in the Jejunum after Cholera Exotoxin Exposure

Abstract

Unidirectional fluxes of sodium were measured in jejunal loops of rabbits exposed to cholera exotoxin. It was found that exotoxin caused an increased flux of Na+ into the lumen, while flux out of the lumen was not changed significantly. It was shown previously that cycloheximide, an inhibitor of protein synthesis, prevents cholera exotoxininduced fluid production by the intestine. Measurement of unidirectional flux demonstrated that cycloheximide completely abolished the cholera exotoxin-induced increase in Na+ flux into the loop while not significantly altering flux out of the loop. It is concluded that cycloheximide prevents the fluid production of intestinal loops exposed to cholera exotoxin solely by blocking the increased flux of Na+ and water into the loop.