Abstract
Changes in serum prolactin concentration were investigated in women taking an oral contraceptive pill and patients treated with combined estrogen-gestagen regimens for uterine endometriosis. The serum prolactin value increased more than twice the initial level one week after the beginning of medication and continued to increase over succeeding three weeks, and it returned to the normal value at one week after discontinuation of the medication. The results obtained demonstrate that an inverse correlation of prolactin and gonadotropin secretions occurred during administration of the steroid sex hormones as seen in post partum period or patients with galactorrhea-amenorrhea. Side effects which may be associated with such combined steroid hormone has also been discussed.