title: A critical period for positive feedback in immature (21-day-old) rats.
mesh_terms: D000375:Aging; D000818:Animals; D002369:Castration; D002940:Circadian Rhythm; D004958:Estradiol / Q000494:pharmacology*; D005246:Feedback; D005260:Female; D007986:Luteinizing Hormone / Q000097:blood*; D008297:Male; D011374:Progesterone / Q000494:pharmacology; D011388:Prolactin / Q000097:blood*; D051381:Rats; D012737:Sex Factors
chemical_list: D011374:Progesterone; D004958:Estradiol; D011388:Prolactin; D007986:Luteinizing Hormone