title: Longitudinal studies of estrous cyclicity in aging C57BL/6J mice: II. Cessation of cyclicity and the duration of persistent vaginal cornification.
abstract: The of onset of acyclicity and the duration of persistent vaginal cornification (PVC), the predominant postcyclic anovulatory condition, were measured in five cohorts of virgin mice staggered across a 6-yr interval. The average age of cessation of cyclicity varied significantly among cohorts, ranging from 11 to 16 mo of age. Seventy-five percent of the mice entered PVC after ceasing to cycle, the remainder entered directly into a persistent diestrous condition. The duration of PVC, which averaged between 2 and 4 mo, varied markedly among individuals and was inversely related to the age of onset of acyclicity. Consequently, the variance associated with the cessation of cyclicity was about 4-fold greater than that associated with the cessation of PVC. These differing variances suggest that the factors governing ovulatory failure and PVC cessation may differ.
mesh_terms: D000375:Aging; D000818:Animals; D000858:Anovulation / Q000473:pathology; D004967:Estrogens / Q000502:physiology; D004971:Estrus; D005260:Female; D051379:Mice; D008810:Mice, Inbred C57BL; D011247:Pregnancy; D014621:Vagina / Q000473:pathology*
chemical_list: D004967:Estrogens