Which toxin is not mediated by cAMP-

Ans. is 'b' i.e., Heat Stable E.coli toxin . Heat labile toxin of E. coli and cholera toxin resemble each other in their structure, antigenic propeies and mode ofaction. Both act by activating adenyl cyclase in the enterocyte to form cyclic adenosine 5' monophosphate (c AMP). . Heat stable toxin of E. coli acts by activation of cyclic guanosine monophosphate (c GMP) in the intestine.