title: The postpubertal change in the playful defense of male rats depends upon neonatal exposure to gonadal hormones.
abstract: The pattern of playful defense used during play fighting by male rats (Rattus norvegicus) castrated at birth was compared to that of sham-operated and untreated controls during the juvenile phase and after puberty. The neonatal castrates failed to exhibit the age-related changes in playful defense present in intact male rats of the same age. Following puberty, control rats, but not neonatal castrates, switched from juvenile to more adult-typical defensive tactics. That the neonatal castrations were effective was independently shown by the animals' failure to exhibit the asymmetries in weight and play behavior indicative of dominance-subordinance relationships present in normal adult males. A previous study found that castration following weaning did not prevent the pubertal change in playful defense, but did block the formation of dominance-subordinance relationships. Therefore, it appears that the age-related shift in playful defense is a feature of the development of play fighting in males that is likely preprogrammed by gonadal hormone exposure in the perinatal period.
authors.affiliation: Department of Psychology and Neuroscience, University of Lethbridge, Canada.
authors.forename: L K
authors.initials: LK
authors.lastname: Smith
authors.forename: M L
authors.initials: ML
authors.lastname: Forgie
authors.forename: S M
authors.initials: SM
authors.lastname: Pellis
mesh_terms: D000374:Aggression / Q000502:physiology*; D000375:Aging / Q000502:physiology / Q000523:psychology*; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D001835:Body Weight / Q000502:physiology; D004291:Dominance-Subordination; D012739:Gonadal Steroid Hormones / Q000502:physiology*; D008297:Male; D009919:Orchiectomy; D010988:Play and Playthings / Q000523:psychology*; D051381:Rats
chemical_list: D012739:Gonadal Steroid Hormones