Comparison of Secretory and Histological Effects of Shigella and Cholera Enterotoxins in Rabbit Jejunum

The purpose of this study was to compare the actions of shigella toxin and cholera toxin to determine if mucosal damage is a prerequisite for shigella toxin-induced secretion. The secretory response to maximal doses of cholera toxin and shigella toxin were compared. The maximal rate of secretion and the electrolyte and protein concentration of the intestinal fluid were similar for both toxins. On the other hand, the time of onset after exposure to the toxin was 105 min for shigella toxin and 15 to 30 min for cholera toxin. In addition, cholera toxin-induced secretion was associated with depletion of goblet cell mucus, whereas no change was seen in association with the response to shigella toxin. Other than goblet cell depletion, there were no histological differences between loops secreting in response to cholera toxin and to shigella toxin. Finally, the secretory effect of the toxins are not additive. These studies suggest that, in spite of apparent differences in the patterns of secretory response to the two toxins, they may share a rate-limiting step in the secretory process.