Effects of neonatal septal lesions on reproductive behavior of male and female rats

Abstract

The purpose of this study was to examine the effects of neonatally placed septal lesions (SL) in male, female, and androgenized female rats on reproductive behavior. Animals were castrated as adults and tested for both feminine and masculine sexual behavior. After treatment with estradiol benzoate (EB) alone (2 μg daily for 3 days), only the females with SL which had not been given testosterone propionate (TP) neonatally showed a facilitation of lordosis behavior. Following EB (2 μg for 3 days) plus 0.5 mg progesterone (P), both the lesioned and the sham-operated female groups showed an increase in the display of lordosis in either hormonal condition. All animals were given a pretest for masculine sexual behavior and tested on Days 4, 7, 11, and 15 of daily TP treatment (150 μg/day). There was no effect of the neonatally placed SL on masculine sexual behavior in female rats or in female rats androgenized with 30 μg TP. However, lesioned females treated neonatally with 1 mg TP showed a marginal enhancement of masculine sexual behavior. Male rats given SL neonatally showed a marked enhancement of masculine sexual behavior compared to that of controls. These results suggest that, depending on the neonatal hormone environment, SL selectively increase behavioral sensitivity to hormones. Although neonatally lesioned females show behavioral responses similar to females given SL as adults, male rats given SL neonatally are unique in that they show enhanced masculine sexual behavior whereas males lesioned as adults do not.