Malabsorption of long-chain fatty acid in cholera toxin-induced secretory diarrhea

The effects of cholera toxin-induced diarrhea on the absorption of fatty acids of different chain lengths were investigated using rat small intestine. In the study using isolated jejunal loops, the absorption of the long-chain fatty acid, linoleic acid, into the intestinal mucosa was significantly impaired 90 min after the administration of linoleic acid micelles in the cholera toxin-treated rats. This reduction of linoleic acid absorption in the cholera toxin-treated rats was not found at 180 min. We could not find any mucosal accumulation of labeled linoleic acid or disturbance of triglyceride formation in the intestinal mucosa as compared with that of controls. The amount of linoleic acid transported into the intestinal lymph was delayed and reduced in cholera toxin-treated rats. Furthermore, the absorption of the medium-chain-length fatty acid, octanoic acid, was unchanged in the cholera toxin-treated rats. These results suggest that intestinal secretion induced by cholera toxin may delay the mucosal uptake and lymphatic transport of long-chain fatty acids. Cholera toxin may not affect triglyceride formation in the epithelial cells.