Inhibition of water absorption by ricinoleic acid - Evidence against hormonal mediation of the effect

In three dogs, each with a jejunal and an ileal Thiry-Vella loop, the isolated segments were perfused with isotonic electrolyte solutions (control) for 90 min. One loop was then perfused with 5 mM ricinoleic acid for an additional 90 min, while the other loop was perfused with the control solution. Loops perfused with ricinoleci acid all showed reduced fluid absorption. Perfusion of one loop with ricinoleic acid produced no changes in fluid absorption from the loop perfused with the control solution. In other experiments, 4 Ivy dog units (IDU) per kg per hr of cholecystokinin (CCK) produced no change in water movement in loops perfused with control solution or ricinoleic acid. These experiments suggest that the effect of ricinoleic acid on intestinal water transport is not mediated through the release of a circulating humoral substance.