Influence of cyclic nucleotides on amphibian ectoderm.

Isolated amphibian (Triturus alpestris) gastrula ectoderm was treated with cyclic nucleotides for 24 h and cultured up to 12 days. Explants treated with$cyclic N6-Monobutyryl-adenosine-3'∶5'-monophosphate, cyclic Dibutyryladenosine-3'∶5'-monophosphate and cyclic Dibutyrylguanosine-3'∶5'-monophosphate in a concentration of 10-3 and 10-5 M did not differentiate into mesoderm- or endoderm-derived tissues. The number of explants with small neural and neuroid structures did not exceed the percentage found in the control series. Inductions could also not be obtained when ectoderm was dissociated prior to the treatment with cyclic nucleotides, or when theophylline (which inhibits phosphodiesterase) was added to the culture medium. The results are discussed with regard to the possible mode of action of the vegetalizing factor.