Effects of mechanical stimulation of the ovarian pedicle on induced ovulation in the prepubertal rat

The innervation reaching the ovaries by the ovarian pedicle participates in regulating the response of ovarian follicles to gonadotrophins. The aim of our study was to analyse the effects of mechanical manipulation of the ova rian pedicle on spontaneous and induced ovulation performed in the peripube rtal period. 32-day old rats subjected to mechanical manipulation were inje cted with 8 U of pregnant mare's serum gonadotrophin (PMSG), 10 U of human chorionic gonadotrophin (hCG) or 8 U of PMSG, followed 56 h later by 10 U h CG. The treatments were given immediately after surgery, and the rats kille d on the day of first vaginal oestrus. In those animals subjected to unilat eral or bilateral mechanical stimulation of the ovarian pedicle, the ovulat ion rate and number of ova shed were similar to those of the control group, when the injection of PMSG or hCG was performed immediately after pedicle manipulation. When both gonadotrophins were administered, the total number of ova shed was significantly higher than in the control or sham operated g roups (left stimulation 17.3 +/- 0.7, right stimulation 17.6 +/- 0.5, bilat eral stimulation 17.5 +/- 0.4 vs control 9.6 +/- 0.2, sham operated 11.9 +/ - 1.3, P < 0.05). These results suggest that the innervation reaching the o vary via the ovarian pedicle regulates, in a stimulatory way, the effects o f gonadotrophin, resulting in ovulation. Med Sci Res 27:561-564 (C) 1999 Li ppincott Williams & Wilkins.