[Ultrastructural changes in rat colon epitheliocytes after treatment with cholera toxin].

Ultrastructural changes in adenylate cyclase activity in the columnar and goblet cells of the rat colon were studied 10, 30 min and 1, 4, 6, 12 and 24 h following injection of cholera toxin (choleragen) into the small intestine of 60 animals. The toxin rather quickly (within 30 min) reached the colon and stimulated membrane-bound adenylate cyclase activity in the colonic columnar and goblet cells. Ultrastructural alterations in the columnar cells, which were comparable to those previously described in choleragen-treated small intestine but were considerably less pronounced, could be detected 1-12 h following the toxin injection. In the colon, stimulation of mucus production by the goblet cells was much more pronounced than in the small intestine. The data obtained suggest that colon is succeptible to the action of choleragen but they cannot be interpreted as an indication of its disturbed re-absorptive capacity.