Partial denervation of the ovaries by transection of the suspensory ligament does not inhibit ovulation in rats treated with pregnant mare serum gonadotropin.

Adrenergic nerves reach the ovary via two routes: along the arteries to the ovary and via the suspensory ligament. Results from earlier investigations suggest that denervation of the nerves along the arteries does not influence the ovulatory process. In the present study we have examined whether denervation by transection of the ovarian suspensory ligament influences the ovulatory process. Partial denervation of the ovary by transection of the ovarian suspensory ligament, sham operation, or only anesthesia were performed on immature 25-day-old rats. To induce ovulation, pregnant mare serum gonadotropin (PMSG) was injected in the morning (0800-0930), when the rats were 26 days old. This PMSG treatment normally induces ovulation around 0200 in the early morning of day 29 with subsequent formation of corpora lutea. Rats were killed 5-8 hr, 3 days, and 5 days after this ovulation time. Ovarian interstitial norepinephrine levels were markedly decreased after transection of the suspensory ligament. Ovulations had occurred in all denervated, as well as sham-operated, and control rats. The various groups did not differ in the number of ovulations per rat. Thus, the adrenergic nerves in the suspensory ligament appear not to be necessary for ovulation. Whether catecholamines themselves play a role in the ovulatory process cannot be elucidated from this experiment, since the norepinephrine content in the ovary was not totally depleted. It seems unlikely that adrenergic nerves reach the corpus luteum via the suspensory ligament, since transection of this structure did not change the luteal content of norepinephrine.