GnRH antagonist-induced down-regulation of the mRNA expression of pituitary receptors: comparisons with GnRH agonist effects.

In order to compare the mechanism for the down regulation of the mRNA expression of pituitary receptors induced by GnRH antagonist (GnRHant) to that by GnRH agonist (GnRHa), we examined the effects of GnRHant (Cetrorelix, 333 mug/kg/day), GnRHa (leuprolide depot, 333 microg/kg), and GnRHant combined with GnRHa on LH response to exogenous GnRH, pituitary LH content, LH beta subunit mRNA, and GnRH receptor (GnRH-R) mRNA levels at 2, 5, 24, 72 hours, and 7 days after the treatment in ovariectomized rats. GnRHant significantly decreased serum LH, the LH response of the pituitary to exogenous GnRH, and the pituitary LH content compared to the control treatment, though GnRHa significantly increased serum LH. GnRHant with GnRHa significantly diminished the GnRHa-induced flare-up phenomenon.

Role of corticotropin-releasing hormone in ovarian steroidogenesis.

The physiologic role of corticotropin-releasing hormone (CRH) was examined in the ovary. We investigated the effects of CRH on steroidogenesis in rat and human granulosa cells in vitro as well as the direct effects of CRH on the ovary in vivo. We further examined the gene expression of CRH in human granulosa cells.

A modified hMG-GnRH method for the induction of ovulation in infertile women with severe hypogonadotropic amenorrhea.

The objective of this study was to compare, in infertile women suffering from severe hypogonadotropic amenorrhea, the therapeutic utility and the incidence of complications arising from fertility treatment by the conventional human menopausal gonadotropin/human chorionic gonadotropin (hMG-hCG) method, the hMG step-down method, the sequential hMG/gonadotropin-releasing hormone (GnRH) method and a new, modified hMG-GnRH method that has been developed by us. In the step-down method, the daily dose of hMG was decreased from 150 IU to 75 IU when the follicle diameter reached 11-13 mm. In the sequential hMG-GnRH, hMG injection was switched to pulsatile GnRH administration (20 microg/120 min SC), when the follicle diameter reached 11-13 mm.