['It has been demonstrated that ethanol decreases blood luteinizing hormone (LH) levels in rodents. This effect seems to be produced by the capacity of ethanol to release beta-endorphins from the hypothalamic arcuate nucleus and, in a second step, by a mu-receptor-mediated inhibitory effect of these peptides on hypothalamic LH-releasing hormone-synthesizing neurons. However, it has been reported that, in primary hypothalamic cultures, the ethanol-produced beta-endorphin release is mediated by the enzyme catalase. Therefore, the aim of this study was to assess whether catalase inhibition modifies ethanol effects on blood LH levels.', 'Swiss albino mice were pretreated with the catalase inhibitor 3-amino-1,2,4-triazole (AT; 0.0-0.5 g/kg) and, 3.5 hr later, saline, ethanol (2.5 g/kg), or morphine (30 mg/kg) was administered. Blood samples were collected 2 hr after ethanol administration, and LH levels were immunoenzymatically assayed.', 'The catalase inhibitor AT dose-dependently blocked the ethanol-produced decrease in blood LH levels without altering those observed after saline or morphine administration. This effect was highly correlated with the decrease in brain catalase activity produced by AT.'] Does brain catalase inhibition block ethanol-related decrease of blood luteinizing hormone levels in mice?