Associations of corticosterone and testosterone with alcohol drinking in F2 populations derived from AA and ANA rat lines.

Abstract In our previous studies on alcohol-preferring AA (Alko alcohol) and nonpreferring ANA (Alko nonalcohol) rats, we have observed that the AA rats exhibit lower endogenous levels of corticosterone, higher testosterone levels, and more frequent alcohol-induced testosterone elevations when compared with ANA rats. The objective of the present study was to get more conclusive evidence for the potential role of the hypothalamus–pituitary–adrenal and hypothalamus–pituitary–gonadal axes in alcohol drinking by using the F2 experimental design. Alcohol-preferring AA and alcohol-nonpreferring ANA rat lines were crossbred to form a F1 population from which the final F2 population was derived. Male animals were challenged with a priming alcohol dose after which a 3 weeks’ voluntary alcohol drinking period took place. After a washout period of 1 week, one-half of the 40 highest and 40 lowest alcohol drinkers were challenged with a second dose of alcohol and the other half with saline. Serum testosterone and corticosterone levels were measured before and during the test. Higher endogenous testosterone levels were detected in the rats of the high alcohol consumption group compared with the low consumption group. Also supporting the original AA/ANA line differences, a trend for lower endogenous corticosterone levels were measured in the high alcohol consumption group compared with the low consumption group. The alcohol challenge test after the drinking period resulted in a higher frequency (38%) of testosterone elevations in the high drinkers compared with the low drinkers (5%). The present data confirms the validity of the positive connections between testosterone elevation and increased alcohol drinking, as well as between testosterone reduction and decreased alcohol drinking, in AA and ANA rats.