The effect of leuprorelin on steroidogenesis of human preovulatory granulosa cells in vitro

Leuprolide acetate reduces both in vivo and in vitro ovarian steroidogenesis in infertile women undergoing assisted reproduction

Despite the probable inhibitory effects of GnRH analogues on ovarian steroidogenesis in vitro, their association with assisted reproduction protocols shows favorable results. This suggests that there are important differences in the behaviors of these drugs when administered in vivo versus in vitro. To clarify these differences, this study was designed to analyze the effect of leuprolide acetate (LA) on ovarian steroidogenesis in women undergoing In Vitro Fertilization (IVF). A prospective, randomized open label study was conducted on 14 women (26-35 years): seven receiving only gonadotrophins (Group 1) and seven receiving gonadotrophin plus LA at 1mg/day (Group 2). The LA in vivo effect was determined with serum and follicular fluid (FF) samples and via luteinized granulosa cell cultivation (GCC), where cells were obtained during oocyte retrieval after ovarian hyperstimulation. In vitro analysis was performed via addition of LA to GCC only for Group 1 (without LA) at progressively higher concentrations (0, 10(-12), 10(-9) and 10(-6)M). In vivo, the main observation was a reduction in androgen production in Group 2, represented by lower androstenedione production in FF (G1=6479+/-3458; G2=3021+/-1119 ng/ml; p=0.04) and a lower testosterone peak in GC at 96h (G1=0.64+/-0.12 ng/ml; G2=0.50+/-0.19 ng/ml; P=0.02), but a higher fertilization rate (G1=67%; G2=83%; p=0.009). In vitro, testosterone, estradiol and progesterone were also reduced by LA, even though this reduction occurred for progesterone only at the highest LA dosage (10(-6)M; 606.0+/-114.3 ng/ml versus 1524.0+/-246.5 ng/ml; p=0.02). Results show that LA reduces ovarian steroidogenesis in vivo by essentially inhibiting androgen synthesis; whereas, in vitro, ovarian steroidogenesis is reduced overall.

Effect of in vivo GnRH agonist and GnRH antagonist on hCG and insulin-stimulated progesterone production by human granulosa-lutein cells in vitro

PURPOSE

To investigate hCG and insulin-stimulated progesterone (P) production by human granulosa-lutein cells (hGLC) in vitro.

METHODS

hGLCs were isolated from patients undergoing IVF-ET cycles in which GnRH agonist or GnRH antagonist was used to prevent a midcycle gonadotropin surge. The cells were cultured for 3 days, and then treated with hCG 0.5, 1, and 10 IU/I, and insulin 0.01, 0.1, and 1 microM in serum free conditions. In vitro P production was measured by enzyme immunoassay.

RESULTS

hCG stimulated P production by hGLCs from cycles in which GnRH antagonist was used, but a blunted response was seen in GnRH-agonist treated cycles. Insulin-stimulated P production was similar in cells from cycles in which GnRH-agonist or GnRH-antagonist treatment was used.

CONCLUSIONS

Because insulin and hCG may share common pathways beyond the level of receptor activation, we hypothesize that GnRH agonist, but not GnRH antagonist, may affect the expression and/or activation of LH receptors in the hGLCs.