Alcohol exposure during late adolescence increases drinking in adult Wistar rats, an effect that is not reduced by finasteride.

AIMS We tested whether an exposure to alcohol in late adolescence, an age of rapid increase in neuroactive steroid precursors, would increase voluntary alcohol consumption in adult rats and whether this effect would be modulated by finasteride, an inhibitor of neuroactive steroid synthesis. METHODS In Experiment 1, we exposed male Wistar rats to 8% alcohol during the dark cycle for 1 week during late adolescence [postnatal days (PNDs) 51-58], and then measured voluntary alcohol consumption 1 month later in adulthood (PNDs 91-104). In Experiment 2, finasteride was administered during the forced alcohol exposure in late adolescence and, in Experiment 3, during voluntary alcohol consumption in adulthood. Plasma was collected at the end of each finasteride treatment to confirm the reduction of plasma neuroactive steroid levels. RESULTS We found that a daily 12-h exposure to alcohol for 7 days in late adolescence significantly increased voluntary alcohol consumption (4-fold) a month later during adulthood. Finasteride administration in late adolescence increased group alcohol intake in late adolescence but did not block the effect of adolescent alcohol exposure on increasing alcohol preference in adulthood. There was no effect of finasteride treatment in adulthood on alcohol preference. CONCLUSIONS A daily 12-h exposure to alcohol for 7 days in late adolescence was sufficient to induce chronically increased alcohol preference in adulthood, indicating that this age may be sensitive to the effects of alcohol.