Effects of gonadotrophin-releasing hormone agonists on human ovarian steroid secretion in vivo and in vitro - results of a prospective, randomized in-vitro fertilization study

The aim of this prospective randomized study was to compare the effects of two gonadotrophin-releasing hormone (GnRH) agonists, buserelin and triptore lin, on human ovarian follicular steroidogenesis, oocyte fertilization and IVF treatment outcome. Ovulatory, healthy women undergoing IVF were treated either with human menopausal gonadotrophin (HMG) alone or with HMG and one of the two GnRH agonists, Serum and follicular fluid hormonal concentratio ns and cultures of luteinizing granulosa cells obtained during follicular a spiration were analysed. GnRH agonist treatment significantly affected ster oidogenesis both in serum and follicular fluid. In follicular fluid, proges terone and oestradiol concentrations were significantly elevated while test osterone concentrations were significantly lower in the triptorelin group, The ratios of testosterone/progesterone, oestradiol/progesterone but not oe stradiol/testosterone concentrations were significantly affected by GnRH ag onist administration. Similarly the steroidogenic activity of luteinizing g ranulosa cells in vitro was significantly decreased in women treated with G nRH agonists, Women treated with GnRH agonists had significantly more ferti lized oocytes and cleaving embryos, The results indicate a marked effect of GnRH agonists on the pattern of ovarian follicular steroidogenesis that ca nnot be explained solely by changes in gonadotrophin concentrations.