GENDER DIFFERENCES IN ETHANOL PREFERENCE AND INGESTION IN RATS - THE ROLE OF THE GONADAL-STEROID ENVIRONMENT

An ethanol oral self administration paradigm showed the existence of g ender differences in alcohol preference in rats: whereas males and fem ales initiated alcohol drinking at similar rates, females maintained t heir preference for ethanol over a longer duration. Neonatal estrogeni zation of females, which effectively confers a male phenotype on a gen etically female brain, resulted in patterns of drinking that were simi lar to those displayed by intact male rats, indicating that gender dif ferences in alcohol drinking patterns may be, at least partially, acco unted for by sexual differentiation of the brain. To test whether gona dal steroids also exert activational effects on ethanol-seeking behavi or, we also examined the effects of gonadectomy alone, or in combinati on with gonadal steroid replacement therapy. Castration did not signif icantly alter ethanol consumption in males, although treatment of cast rated rats with dihydrotestosterone resulted in a significant inhibiti on of this parameter, As compared with the situation in intact female rats, ethanol ingestion was significantly reduced in ovariectomized fe male rats receiving estradiol (E-2) and in ovariectomized female rats receiving combined E-2 and progesterone replacement therapy. However, neither ovariectomy nor progesterone replacement in ovariectomized rat s resulted in ethanol drinking patterns that were different compared t o those observed in intact female controls. Thus, dihydrotestosterone and E-2, respectively, appear to exert modulatory influences on the ma le and female rats' preference for ethanol, but further investigations are necessary to determine to what extent these effects result from a ctivational actions on the brain.