The objective of this study was to determine the responsiveness of isolated embryonic murine and avian epithelial and mesenchymal tissue to PGE2 stimulation. On days 12 and 14 of gestation, murine palatal epithelium responded to PGE2 (10(-5) M) with 3.5 and 4.0 fold elevations in intracellular cAMP, respectively. On day 13 of gestation, murine palatal epithelium was responsive to forskolin, PGE1 and isoproterenol as indicated by the accumulation of cAMP, but unresponsive to PGE2 and PGF2 alpha less than treatment. Avian palatal epithelium and mesenchyme, developmental stages 31 to 34, as well as murine palatal mesenchyme on day 13 of gestation responded to PGE2 treatment with dose-dependent elevations in intracellular cAMP. Of importance, is the lack of responsiveness of murine palatal epithelium to PGE2 treatment on day 13 of gestation. This corresponds to the time of murine palatal medial edge epithelial differentiation. Lack of a PGE2 response may effect, initiate or occur as the result of murine medial edge epithelial differentiation.