Period of maximal susceptibility of the prenatal female guinea pig to masculinizing actions of testosterone propionate.

Abstract

Variations in time of injections of testosteronepropionate during the prenatal period, duration of treatment, and total amount administered were evaluated for effects on sexual be-havior and genital structures of female guinea pigs in adulthood. As in an earlier study, treated females showed a suppression of the capacity to display estrus and an augmentation of mounting in the absence of exogenous ovarian hormones. These effects were greatest when initial doses were given 30 and 35 days of the gestation period regardless of duration of treatment or amount of androgen. Masculinization of genital structures was correlated with behavioral changes, but genital tissues appear to be sensitive somewhat earlier in development than are the neural tissues destined to mediate mating behavior.