Sex and strain differences in ethanol drinking: Effects of gonadectomy

Background: Alcohol drinking behavior in rats is known to be sexually dimor phic and strain-dependent. Methods: To test whether the gonadal steroid milieu exerts activational eff ects on ethanol intake and can modulate individual sensitivity toward alcoh ol use and misuse, we examined the effects of gonadectomy on oral self-admi nistration (OSA) of ethanol in male and female rats from different strains. After castration, animals were given continuous free choice between water and ethanol solutions. The ethanol concentration was progressively increase d from 2% to 10% and maintained at 6% (the preferred concentration) for 24 days. Ethanol solutions were then withdrawn for 9 days. During the second p hase of free-choice drinking, the ethanol concentration was gradually incre ased every 4 days by the following amounts, in order as listed: 6%, 12%,and 24%. Results: Our results confirm both gender and strain differences in ethanol drinking: females exhibited higher ethanol intake than males, and the WKHA strain drank more than the WKY and SBR strains. However, except for a small decrease in ethanol drinking during the acquisition of ethanol OSA in male s after castration, no clear-cut difference was found between gonadectomize d and sham-operated animals during the maintenance of ethanol OSA behavior. Conclusions: These data suggest that gender and strain differences observed are insensitive to gonadal steroids during adulthood, and that different s ensitivities to the effect of gonadal steroids do not explain the sex x str ain interaction observed in ethanol drinking.