[Role of phosphodiesterase in the changes of cyclic adenosine-3',5'-monophosphate in the rabbit jejunal mucosa after treatment with cholera enterotoxin].

An increase in content of cAMP in the rabbit jejunum mucosa after treatment with cholerae toxin was due to adenylate cyclase activation. The maximal activation of adenylate cyclase (AC) and increase in the cAMP content in the mucosa were observed within 4 hrs after administration of the cholerae toxin in situ into the lumen of an isolated strip of the rabbit jejunum. Cholerae enterotoxin did not affect the activity of phosphodiesterase (PDE). It was shown that AC activation did not correlate with an increase in the cAMP content in rabbit jejunum mucosa exposed to cholerae enterotoxin. Absence of the correlation was demonstrated by kinetic characteristics of PDE and by regulatory effect of Ca2+ on the activity of AC and PDE.