Haploinsufficiency of the follicle-stimulating hormone receptor accelerates oocyte loss inducing early reproductive senescence and biological aging in mice.

Female mice that are null for the FSH-receptor (FSH-R) gene are estrogen deficient, acyclic, and sterile. However, the heterozygous (+/-) mice initially have reduced fertility and stop breeding by 7-9 mo. The purpose of this study was to understand the basis of reduced fertility in mice with haploinsufficiency of the FSH-R. Heterozygous females were compared to +/+ females at 3, 7, and 12 mo of age. By 7 mo most of the +/- females were acyclic and <50% delivered pups. The wild-type females were normal in these respects. None of the 1-yr-old +/- females gave viable offspring (73% in +/+). Many degenerative changes, including atresia and apoptosis, and profound loss of oocytes, were apparent in +/- mice by 7 mo. The 1-yr-old +/- ovary had very few follicles and consisted mostly of fibroid tissue and cysts. Our data support the hypothesis that reproductive deficits in +/- FSH-R mice occur because of accelerated oocyte loss due to increased cell death in the ovary. These events contribute to early reproductive senescence and biological aging in mice. Thus FSH-R status is an important determinant of ovarian aging and all phenomena that arise from subsequent estrogen deficiency and other aberrations.