The longtime application of oral contraceptives is assumed to elevate serum prolactin levels under non-stimulated conditions. We therefore examined whether oral contraceptives also will augment prolactin secretion after stimulation, e.g. by thyrotropin releasing hormone (TRH). After TRH stimulation the time sequence of secretion both of prolactin (HPRL) and thyroid stimulating hormone (TSH) was determined. Three groups of women were tested in a non-randomized study: group 1 without any hormonal medication (= controls), group 2 taking an oral contraceptives containing cyproterone acetate, group 3 using an oral contraceptive containing d-norgestrel. HPRL secretion was similar in all three groups, the same held true for TSH. A possible correlation between the secretion of HPRL and TSH was examined in the control group. No such correlation was found. The secretion patterns of both hormones also were different. In addition, the basic levels of both HPRL and TSH did not seem to influence the response after stimulation.