Intestinal villus and crypt cell responses to cholera toxin

Adenylate cyclase activity was measured in rat small intestinal villus and crypt cells after in vivo and in vitro exposure to cholera toxin. The increase in intestinal adenylate cyclase induced by cholera toxin in vivo appeared to be largely confined to the villus cell with the largest increase observed for upper villus cells. Crypt cell adenylate cyclase was not responsive to cholera toxin. No response could be demonstrated for isolated villus or crypt cells incubated with cholera toxin in vitro. In vivo incubation with 125I-cholera toxin demonstrated binding to only villus cells. These results suggest that the major effect of cholera toxin was on villus cells rather than crypt cells and this was due to the greater accessibility or binding capacity of the villus cell to luminal cholera toxin.