Two experiments were conducted to evaluate the effects of methanol (MEOH) on the serum hormones associated with reproductive function in the male rat. First, rats were exposed to MEOH for 6 hs and killed immediately or 24 hs later. The effect of the handling associated with placing the rat in the exposure chamber was also evaluated by comparing hormonal changes in sham- and MEOH-exposed groups acclimated (A) for two weeks with groups that were not acclimated (N-A). At 6 h, serum LH in sham-exposed, NA rats was significantly greater than in sham-exposed, A rats. 5,000 ppm MEOH significantly reduced serum LH in the N-A rats, while 10,000 ppm significantly increased serum LH in the A rats. Serum FSH and testosterone (T) were not different at 6 h. At 24 h, serum LH in A rats exposed to 10,000 ppm MEOH was greater than sham-exposed rats. Also, concentrations of serum and interstitial fluid (IF) T in the N-A rats at 24 h was generally greater than that observed in A rats. Serum and IF T in the A rats exposed to 10,000 ppm was lower, while serum and IF T in N-A rats was greater after exposure to 5,000 ppm and 10,000 ppm, respectively. In a second experiment, groups of A and N-A rats were exposed to 5000 ppm MEOH for 1, 2 or 6 h and killed immediately. Serum LH, T and corticosterone concentrations in sham- and MEOH-exposed rats were similar at all time points. However, the concentrations of LH and T in the N-A rats were greater than A rats after 1 and 6 h exposure, while that of corticosterone was greater at 1 and 6 h.