Twenty-one hour light-dark cycle accelerates vaginal opening in the rat.
D000818:Animals; D002940:Circadian Rhythm; D003624:Darkness; D004971:Estrus; D005260:Female; D006065:Gonadotropins, Pituitary / Q000096:biosynthesis; D008027:Light; D011247:Pregnancy; D051381:Rats; D014621:Vagina / Q000502:physiology*
D006065:Gonadotropins, Pituitary