Cytochemical localization of adenyl cyclase in the rat colonic mucosa.

Adenyl cyclase has been demonstrated in the colonic mucosa with the aid of adenylyl-imidodiphosphate as a specific substrate. Coarse precipitates are located mainly in the basement membrane and in the junctional area between two epithelial cells and on the brush border of all epithelial cells of the descending colon. Hydrolysis of the substrate was found to be accelerated by 10 mM sodium fluoride in the incubation medium. However, in the ascending colon, the precipitate appeared only in the brush border.