Concentrations of steroid hormones, and of prolactin, in washings of the human uterus during the menstrual cycle

Abstract

Levels of steroid hormones, prolactin and protein were determined in trans-cervical flushings of uteri of 73 consenting women presenting for reversal of sterilization. Median total levels of steroids (pmol), prolactin (μi.u.) and protein (mg) in the washings were: pregnenolone, 4.22; pregnenolone sulphate, 15.1; progesterone. 1,01; dehydroepiandrosterone (DHEA), 8.92; DHEA sulphate, 368; androstenedione, 2.23; testosterone, 1.04; oestrone, <0.7; oestrone sulphate, 0.49; oestradiol 0.08; prolactin, 23.8; and protein, 5.75. Levels of these components of uterine flushings did not vary significantly between Days 6-10, 11-14, 15-20 and 21-28 after the onset of the previous menstrual period (P > 0.05). Uniform levels of free steroids in uterine washings throughout the menstrual cycle, and low free steroid/total protein ratios (all < 3 pmol/mg), support other evidence for a paucity of steroid-binding proteins in human histotroph. The predominance of DHEA sulphate and of pregnenolone sulphate in human uterine washings is in accord with their abundance in plasma, and may provide an important precursor pool for de-novo steroidogenesis by human embryos before implantation. Our results support the view that human histotroph is a filtrate of plasma.