Abstract
The estrogen production of the ovarian follicles with maturation and its significance in the ovulatory mechanism were investigated in the laying quail. Estrone and estradiol-17β contents of the wall of growing follicles and of peripheral blood plasma were determined with radioimmunoassay.
Estrogen contents of the medium-sized follicles were high and those of other follicles were negligibly small. Thus the estrogen production of the follicle increases with its rapid growth and ceases abruptly two days before ovulation. During an ovulation cycle, the follicular estrogen levels showed cyclical fluctuation having a peak 4 hr before next ovulation, when the plasma estrogen level showed periodical increase. Surgical removal of the follicles including two medium-sized before the peak of the estrogen level delayed the ovulation of larger follicles and accelerated growth of smaller follicles.
The important roles of estrogen production of the medium-sized follicles in the follicular growth and the ovulation were suggested.
