Effects of Purine and Pyrimidine Analogues on Development of Rana pipiens

Abstract

Antimetabolites related to nucleic acid derivatives inhibit the early embryonic development of R. pipiens at several rather specific morphological stages. Antipurines (8-azaadenine, 6-mercaptopurine) show inhibitory effects at very early stages of development. Folic acid analogues, and 2,4-diaminopyrimidines which have antifolic acid activity, first inhibit at neurulation. At concns. somewhat lower than those required for complete inhibition an analogue may delay development at several successive critical stages.