title: Rats on 22.5-hr light:dark cycles have vaginal opening earlier than rats on 26-hr light:dark cycles.
abstract: Rats on 22.5-hr light:dark cycles had vaginal opening significantly earlier than rats on 26-hr light:dark cycles. This finding might explain the early menarche in blind girls: Their circadian rhythms, like those of rats on 22.5-hr cycles, might be more rapid than normal. Thus a set number of cycles can occur in a shorter time than usual, allowing puberty to take place early.
mesh_terms: D000204:Activity Cycles; D000818:Animals; D001683:Biological Clocks; D002940:Circadian Rhythm; D005260:Female; D051381:Rats; D011919:Rats, Inbred Strains; D012741:Sexual Maturation; D014621:Vagina / Q000502:physiology*