Androgens and the endometrium
The role of C19 steroids in the human endometrium is at present unclear. In order to gain an insight into their action, radioimmunoassay procedures were developed which had sufficient specificity and accuracy to measure testosterone, 5α-DHT, oestradiol, progesterone and androstenedione in endometrial samples. Amounts of androstenedione were greater (range 1.2-20.8 ng/mg tissue) than other steroids. Samples were obtained from patients presenting with a variety of conditions: subfertility, postmenopausal bleeding, dysfunctional uterine bleeding and abdominal pain. Patients admitted for sterilisation were used as normal controls. A significant positive correlation (r = 0.80) was found between the levels of testosterone and 5α-DHT measured in the same tissue which suggests the presence of a 5α reductase enzyme. No relationship was observed in tissue steroid concentration and age of the patients. Steroid concentrations were found to be high in tissues obtained from patients with endometrial carcinomas whereas progesterone concentration being low in subfertiles. The oestrogen, progesterone and androgen receptor levels of endometrial tissues from subfertile women were also determined using the DCC technique and not the procedure based on protamine sulphate precipitation since endometrial tissue available was very small. No correlation was found between receptor binding sites and day of cycle for any of the three steroids analysed; nor was there any correlation between age and receptor binding sites. A cyclic variation followed by normal women was seen in the oestrogen and progesterone receptor concentrations in the menstrual cycle. Such a variation was also observed in subfertile women on clomiphene citrate therapy. It is concluded that normal endometrium contains measurable quantities of androgens and that a receptor for 5α-DHT is present. The difference in steroid concentrations between normal and pathological states suggest that C19 steroids may be induced in the development of abnormalities.