Concentration of Electron Dense Granules in the Rabbit Ovarian Surface Epithelium During Ovulation

Abstract

The rabbit ovary was examined to determine the distribution of electron dense granules in the cells of the surface epithelium during ovulation. The granules in the epithelial cells covering mature follicles increase from a mean frequency of 1.83 ± 1.96 per cell in the unmated animal to a mean of 3.88 ± 2.02 at 9 h after mating. (The cross-sectional area of the surface epithelial cell remains constant to 9 h.) The concentration of the granules remains elevated until rupture of the follicles (i.e. approx. 9.5 h postcoitum). Within 2.5 h after ovulation the granule concentration decreases to the level of unmated mature follicles. Dense granules are also present in the surface epithelial cells which cover the ovarian stroma, indicating they are not restricted just to the apex of mature follicles. In addition, some follicles proceeded to rupture even after the surface epithelium had been removed by scraping the surface of the ovary. These results suggest that the accumulation of electron dense granules in the surface epithelium of the rabbit ovary is not essential to ovulation. The increase in their concentration during ovulation may reflect a physiological response of the ovarian surface to the traumatic changes which occur in a mature follicle as it approaches rupture.