[Aging phenomena of granulosa cells in the human ovary]

The human ovary ceases its function far earlier than that of other endocrine organs. For the study of the mechanism of decreasing ovarian function with aging, the functional changes in follicular granulosa cells (G-cells) which are indispensable to existing of oocytes were investigated. 1) The mitotic frequency which was calculated in G-cells of antral follicles in tissue preparation decreased markedly in over 40 year old women who are in climacterium. 2) Also the mitotic frequency of cultured G-cells which are removed factors of aging from a living body decreased after 40 years old. 3) In order to study DNA synthetic ability of cultured G-cells, 3H-thymidine up-take to the nuclei of G-cells was examined. It was also decreased in climacterium. 4) E2 production of cultured G-cells also decreased in women in 40's. 5) The binding activity of 125I-FSH and 125I-LH on the membranes of cultured G-cells were also decreased with aging. These data indicate that the decrease of DNA synthetic ability, multiplication, steroidogenesis, and gonadotropin binding activity of granulosa cells which are indispensable to existing oocyte is playing major role in aging and cessation of human ovary.