The aim of our in vitro experiments was to discover the effects of steroid hormones (progesterone, androstenedione and estradiol-17 beta, 10, 100, 1000 or 10,000 pg/ml medium) on the output of cyclic nucleotides adenosine 2',3'-cyclic monophosphate (cAMP) and guanosine 2',3'-cyclic monophosphate (cGMP) by granulosa cells isolated from human ovaries. The dramatic increase of cAMP release after progesterone treatment was observed. Low doses of androstenedione (10 or 100 pg/ml) significantly decreased while higher doses (1000 or 10,000 pg/ml) tended to increase cAMP output. All doses of estradiol significantly inhibited cAMP release. Low doses (10 or 100 pg/ml) of all investigated steroid inhibited while higher doses (1000 or 10,000 pg/ml) stimulated cGMP output. cGMP-stimulating effects of progesterone and androstenedione were expressed significantly more than that of estradiol. The influence of progestagen, androgen and estrogen on cyclic nucleotide release by granulosa cells may suggest the involvement of cAMP- and cGMP-dependent intracellular mechanisms in the realization of steroid hormone effects within human ovaries.