Morphogenetic effect of cAMP during the metamorphosis of the frog larva

In an in vitro system, the tail absorption of the frog larva was significantly stimulated by cAMP more intensely than by T3. Theophylline, an inhibitor of cPDE, had no effect and failed to enhance, even decreased the effect of T3. It may be supposed that T3 does not act through a cAMP mechanism, but the tail absorption can be influenced by cAMP in a direct way.