When used in excess quantities, ethanol (ETOH) is a major drug of abuse with deleterious effects on the male and female hypothalamic-pituitary- gonadal axis. The molecular and cellular mechanistic details of such effects have been and are being studied intensively by our laboratory and others in the male rat. In contrast, however, there has been relatively little in depth study of ethanol's effects on the hypothalamic-pituitary- gonadal axis of the adult, post-pubertal female rat. The studies that do exist suggest that there is a potent effect of ETOH as well. The specific hypothesis to be tested is: ACUTE AND CHRONIC ETHANOL ADMINISTRATION DISRUPTS THE ESTROUS CYCLE BY DIMINISHING STEADY STATE LEVELS OF HYPOTHALAMUS PRE-PRO LUTEINIZING HORMONE RELEASING HORMONE (LHRH) mRNA AND BY IMPAIRING CONVERSION OF PRO LHRH TO BIOACTIVE LHRH. THIS LEADS TO PITUITARY GONADOTROPIN FAILURE AND SECONDARY GONADAL FAILURE. Data to prove or refute this hypothesis will be obtained in the course of accomplishing TWO specific aims. A. To determine on each day of the estrous cycle the effect of a single IP injection of ethanol (compared to IP saline) on pre-proLHRH gene expression (by reverse transcription/polymerase chain reaction), proLHRH processing to the mature bioactive LHRH decapeptide (by RIA with antibodies specific for either precursor or product), pituitary gonadotropin gene expression (by Northern analysis), and content, serum gonadotropin levels, and ovarian weight, histology and hormonal function (as assessed by serum estradiol and progesterone and uterine weight and histology) (Experiment 1). B. To determine the effects of two months of feeding of a liquid ETOH containing diet (compared to pair fed liquid control diet) on the same parameters as in Specific Aim A (Experiment 2). In the first experiment, a single IP injection of ETOH (or saline control) will be given at 1:00 p.m. on each day of the estrous cycle. Thereafter, animals will be sacrificed on proestrous at 3, 4, 5, 6, 7 and 9 p.m. in order to capture the proestrous surge of LH and FSH. On other days of the estrous cycle, after ethanol injection at 1:00 p.m., animals will be killed only at 4:00 p.m. In Experiment 2, sacrifice times will be similar to those in Experiment 1.