Abstract
The cell biology of ovarian surface epithelium (OSE) was studied in mice of varying age and lifetime total ovulation number (OV#), to determine the relative importance of these factors in control of OSE proliferation and development of invaginations and cysts. Ovaries from Swiss Webster mice (total OV# median: range [n mice]) were collected at 4 weeks of age (prepubertal; 0[9]), from 3-month virgins (113: 11-235 [55]), from 12-month old breeders (217: 97-386 [21]) and from 8-month virgin mice, housed in split cages alongside a male, to induce continuous oestrous cycles (629: 456-908 [16]). Scanning electron microscopy revealed cuboidal and squamous cells in OSE from all ages. Higher total OV# markedly increased the rate of OSE invagination and layering. Histology showed the incidence of cysts, which had the appearance of benign serous cystadenomata, increased with age rather than total OV#.