We have investigated the effects of bisphenol A (BPA) and BPA-dimethacrylate (BPA-DMA), endocrine disruptors used as plasticizers, on steroid hormone production by porcine ovarian granulosa cells after 72 h incubation. BPA at 10(-8) M to 10(-5) M increased basal progesterone levels, while the same concentration range of BPA-DMA did not cause any changes. After FSH-stimulation of the cells, BPA-DMA showed a tendency to inhibit progesterone production. BPA, however, at 10(-7) M and 10(-6) M concentrations was even able to amplify FSH-stimulated progesterone synthesis. BPA as well as BPA-DMA inhibited FSH-induced estradiol production in the whole concentration range. LH-stimulated progesterone production was not altered by BPA in 10(-8) M to 10(-5) M, while BPA-DMA decreased progesterone levels in the cultured media. Significant inhibitory effect of both tested agents at 10(-4) M concentrations was observed specifically on progesterone production, basal as well as gonadotropin-stimulated. The results indicate that ovarian steroidogenesis might be one of the possible sites afflicted by the endocrine disrupting action of BPA and BPA-DMA.