Increase in epithelial cyclic adenosine 3',5'-monophosphate following vanadate

Vanadate increases the cyclic adenosine 3',5'-monophosphate (cyclic AMP) content of frog skin epithelium and apparently antagonizes the stimulation by isoprenaline. The effect appears to be a direct activation of adenyl cyclase. This new effect of vanadate together with the inhibitory effects on Na-K ATPase may explain the irregular effects on sodium transport.