The studies reported in this paper were undertaken to investigate the effect of chronic (10 day) alcohol consumption on female pituitary-gonadal function. The immature female rat model treated with pregnant mare serum gonadotropin (PMSG) was used since it results in a highly reproducible luteinizing hormone (LH) surge and ovulation. Twenty-day-old female rats were placed on diets that were either (1) unrestricted (ad libitum); (2) contained 5% ethanol in a liquid diet, or (3) isocalorically pair-fed with the liquid diet to the ethanol group. After 10 days on their respective diets, the groups were subdivided and given either 8 IU of PMSG in 0.1 ml saline or 0.1 ml saline s.c. between 10.00 and 11.00 h. The animals were sacrificed by decapitation at 24, 48, 52, 54, 56, 58, 60 and 62 h after injection. Trunk blood was obtained for serum measurements of LH. The uteri were weighed and prepared for the histological study. In all dietary groups, serum LH levels were significantly higher in the PMSG-treated animals when compared to the saline controls at all time intervals with the exception of the alcohol 58-hour group. In the ad libitum animals, plasma LH concentrations were highest at 52 h following hormone administration. The serum LH concentrations were highest at 56 h after hormone administration in the pair-fed group and were significantly less than the ad libitum group at 52, 54, 56, and 58 h after PMSG stimulation. No significant plasma LH surge was observed in the alcohol group and the LH concentrations were significantly less than the pair-fed rats at 56 and 58 h after PMSG treatment. In contrast to the alterations in LH levels, the PMSG-induced increase in uterine weights and histological evidence of estrogenization were not as dramatically changed by any of the dietary modifications. Thus, chronic alcohol consumption appears to have a greater effect on pituitary gonadotropin secretion than on the gonadal aspects of reproductive function. These studies further suggest that caloric restriction in both the alcohol and pair-fed animals significantly decreased PMSG-induced LH release. Nonetheless, chronic alcohol consumption causes an additional impairment which may be manifest throughout the hypothalamic-pituitary-gonadal axis.