Attenuating activity of the ovary on LH response to GnRH during the follicular phase of the cycle.

Oestradiol sensitizes the pituitary to GnRH, while gonadotrophin surge attenuating factor (GnSAF) may oppose this action. Using the LH response to GnRH during treatment with FSH as an in vivo bioassay for GnSAF, we tested the hypothesis that the augmented LH response to GnRH in the late follicular phase is related to reduced production of GnSAF from the ovulatory follicle. Prospective intervention study. Ten healthy, normally cycling women. The LH response to 10 μg GnRH i.v. (ΔLH) was investigated on days 2 and 3 and on days v (follicle size 16-17 mm) and v + 1 of cycle 1 (control) and cycle 2. On days 2 and v, a single s.c. injection of either normal saline (cycle 1) or 450 IU recombinant FSH (cycle 2) was given after the end of the GnRH experiment. FSH injection increased both serum oestradiol and inhibin B. In cycle 1, ΔLH remained unchanged from days 2 to 3 but increased significantly from days v to v + 1. In contrast, in cycle 2, ΔLH decreased significantly from days 2 to 3 (P < 0·05) and showed a nonsignificant increase from day v to day v + 1. The percentage difference in ΔLH between cycle 1 and cycle 2 was similar on days 3 (-66·9 ± 17·5%) and v + 1 (-65·2 ± 3·6%). These results suggest that during the follicular phase of the menstrual cycle, GnSAF is produced by small antral follicles, while the contribution of the ovulatory follicle is minimal.

Dimitraki M ，Messini CI ，Dafopoulos K ，Gioka T ，Koutlaki N ，Garas A ，Georgoulias P ，Messinis IE ... -  《-》

Luteinizing hormone response to gonadotrophin-releasing hormone in normal women undergoing ovulation induction with urinary or recombinant follicle stimulating hormone.

Messinis IE ，Milingos S ，Zikopoulos K ，Hasiotis G ，Seferiadis K ，Lolis D ... -  《HUMAN REPRODUCTION》

Effect of follicle stimulating hormone or human chorionic gonadotrophin treatment on the production of gonadotrophin surge attenuating factor (GnSAF) during the luteal phase of the human menstrual cycle.

Messinis IE ，Lolis D ，Zikopoulos K ，Milingos S ，Kollios G ，Seferiadis K ，Templeton AA ... -  《CLINICAL ENDOCRINOLOGY》

Changes in pituitary sensitivity to GnRH in estrogen-treated post-menopausal women: evidence that gonadotrophin surge attenuating factor plays a physiological role.

Dafopoulos K ，Kotsovassilis CG ，Milingos S ，Kallitsaris A ，Galazios G ，Zintzaras E ，Sotiros P ，Messinis IE ... -  《-》

Effect of mifepristone (RU486) on the pituitary response to gonadotrophin releasing hormone in women.

Kazem R ，Messinis LE ，Fowler P ，Groome NP ，Knight PG ，Templeton AA ... -  《HUMAN REPRODUCTION》