The effects of epidermal growth factor (EGF), phorbol 12-myristate 13-acetate (PMA), A23187, and ionomycin on prostaglandin production by chorion laeve cells in culture for 3 days and 10 days were tested. Experiments were conducted at day 3 because at this time the cultures became confluent and again at day 10 because changes have been observed in the biochemical properties of these cells with time in culture. At 3 days of culture the cells did not respond to EGF but at 10 days EGF (10 ng/ml) induced a significant increase in prostaglandin E2 production. PMA (10(-9) to 10(-6) M) induced a significant increase in PGE2 production at both times in culture. The calcium ionophores, A23187 and ionomycin, were less effective in eliciting a response at either time in culture. Only A23187 (1 microM) induced a significant increase in PGE2 production at day 10 of culture. These data suggest that the presence of functional EGF receptors may increase with time in culture. Furthermore, activation of the protein kinase C pathway in the chorion laeve stimulates prostaglandin biosynthesis. On the other hand, chorion laeve cell prostaglandin biosynthesis is not responsive to increases in intracellular calcium induced by mobile ion carriers such as the ionophores used in this study.