Hormone Specificity, Androgen Metabolism, and Social Behavior

SYNOPSIS. The ability of different sex hormones to activatesocial signals can provide important clues to the biochemicalmechanisms underlying these signals. A pattern of hormone specificityin which testosterone (T) and estradiol (E), but not dihydrotestosterone(DHT), are effective suggests that conversion (aromatization)of T to E in the brain may be involved or required; a patternin which T and DHT, but not E, are effective suggests that conversionof T to DHT may be involved. The hormone specificity of socialsignals in diverse species of vertebrates is reviewed. Aromatizationseems to be of widespread behavioral significance in mammalsandbirds. A role for conversion of T to DHT is suggested forsome signals. Aromatization of T mayalso be important for theactivation of adult female behavior in mammals and lizards,and for the early organization of behavior in mammals and birds.Patterns of hormone specificity differ both across species fora given social signal, and within a given species when differentsignals are compared. An attempt is made to integrate thesefindings by relating patterns of hormone specificity to hormonelevels, steroid receptor and enzyme concentrations and distributions,signal function and dimorphism, and phylogenetic status.