EVIDENCE FOR A PRIMARY ABNORMALITY OF THECAL CELL STEROIDOGENESIS IN THE POLYCYSTIC-OVARY-SYNDROME

OBJECTIVE Polycystic ovary syndrome (PCOS) is a common endocrinopathy of unknown aetiology. The aims of this study were to identify whether ovarian thecal cell steroidogenesis is abnormally regulated in PCOS by measuring steroid responses to a single dose of hCG before, and durin g, suppression of endogenous LH levels by a GnRH analogue (GnRHa). DES IGN Serum levels of LH, FSH, 17 alpha hydroxyprogesterone (17OHP), and rostenedione, testosterone and dehydroepiandrosterone sulphate were me asured before, and 48 hours after, a single intramuscular injection of 10 000 IU hCG, The test was repeated 4 weeks after suppression of end ogenous LH levels by GnRHa, PATIENTS The ovarian responses to hCG were compared in three groups of women, Eleven women had normal ovaries an d regular cycles, eight had polycystic ovaries but no clinical feature s of the syndrome (PCO group) and eight had polycystic ovaries, anovul ation and either severe hirsutism or alopecia (PCOS group), RESULTS Be fore GnRHa treatment, LH levels were significantly higher in the PCOS group but hCG stimulated a similar rise in 17OHP in all three groups. Following analogue, LH levels were suppressed in all three groups but the 17OHP responses to hCG were significantly higher in both the PCO a nd PCOS groups compared with normal controls. CONCLUSIONS These findin gs provide further evidence in favour of an intrinsic abnormality of c ell steroidogenesis in the polycystic ovary.