Impact and reversibility of chronic ethanol feeding on the reproductive axis in the peripubertal male rat

Teenage drinking continues to be a major problem in the United States as well as abroad. A significant depression in serum testosterone in adolescents who consume EtOH has been well described. In the male rodent model, a similar fall in testosterone has been reported, and prevention with the opiate blocker naltrexone has been demonstrated. To explore further the impact of chronic EtOH exposure on the reproductive axis in peripubertal rats, we designed this study specifically to define whether or not there was recovery after abstinence by examining reproductive hormones and their genes during and after EtOH exposure. Peripubertal male rats 35 d old were fed an EtOH-containing diet or a calorically matched control diet for 60 d. A third group was fed the control liquid diet ab libitum. EtOH was then withdrawn and all animals were fed standard rat chow and water ad libitum for an additional 3 mo. The EtOH-imbibing animals were found consistently to weigh less than their pair-fed mates and liquid diet ad libitum animals. Serum testosterone levels and testicular weights were significantly decreased by EtOH whereas serum estradiol levels were higher, suggesting enhanced peripheral conversion by EtOH. Spermatogenesis, assessed by histological parameters, was unaltered by EtOH. Serum luteinizing hormone levels were not different among the groups. Hypothalamic luteinizing hormone-releasing hormone mRNA levels were unaffected by EtOH. During the 3-mo recovery period, all the changes reversed, with a significant increase noted in testosterone. All other parameters remained the same among the groups. Thus, although chronic EtOH exposure in the peripubertal age period results in significant reproductive alterations, there is complete recovery on withdrawal.