Abstract
The present experiments were performed to elucidate the mechanism of the selection and maturation of a dominant follicle in women. Eight normally menstruating women undergoing myonectomy or tubal surgery volunteered for the present study. In 3 patients who were operated on Day 9-11, a visual dominant follicle was removed. The other 5 patients underwent the removal of a newly developing corpus luteum on Day 15-21. After taking 3 or 4 preoperative blood samples in the morning after their hospitalization, blood was obtained at 3 or 6h intervals for the first 36-45h and at 1-3day intervals thereafter for 21-34days. Serum FSH, LH, estradiol and progesterone were measured by radioimmunoassay.
Follicleectomy was followed by a sudden drop in estradiol and a minor increase in progesterone. FSH increased for a few days and then declined. There was a drastic, but short-term increase in LH following follicleectomy which was performed before a preovulatory gonadotropin surge. A LH surge occured 10.7±1.2days (mean ±S.E.) after follicular ablation followed by a luteal phase.
In contrast, there was no remarkable LH release in 4 out of 5 patients who underwent luteectomy. A slightly higher level of FSH was sustained for 2-7 postoperative days. “Luteal phase” rises in estradiol and progesterone terminated promptly following luteectomy. A LH surge was observed 14.2±1.7days after surgery followed by a luteal phase. After either type of operation, a sustained increase in FSH was followed by a gradual increase in estradiol which preceded a gonadotropin surge.
These hormonal sequences resemble those seen in the normal follicular phase. The present data demonstrated that follicleectomy and luteectomy bring on some characteristic hormonal changes which may exert stimulatory or suppressive effects on the selection and maturation of a dominant follicle after the removal of a main ovarian cyclic structure culminating in ovulation at a certain interval.
