Corticosterone response to an acute dose of ethanol in naive and ethanol experienced rats

The corticosterone response to an acute dose of ethanol (2 g/Kg, i.p.) was measured in the same rats in three different occasions: prior to, immediately following exposure to ethanol in a free choice self-administration paradigm and after a 15 day period of abstinence following exposure. Corticosterone was measured fluorometrically from tail blood samples collected 30 minutes following the ethanol injection. Blood ethanol levels were determined by gas chromatography. Mean plasma corticosterone and ethanol levels following the acute ethanol challenge were not significantly different in the three tested periods. A significant negative correlation between plasma corticosterone levels in the naive state and subsequent levels of individual voluntary ethanol intake was obtained. No apparent relationship was observed, however, between the same levels of ethanol consumption and the corticosterone response in these animals after ethanol exposure or exposure with abstinence. These data suggest that levels of ethanol intake may be related to the initial response to acute ethanol of the adrenal-pituitary axis. If so, this acute response to ethanol may be used to predict subsequent levels of ethanol intake.