Brain catalase inhibition blocks ethanol-related decrease of blood luteinizing hormone levels in mice.
BACKGROUND
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
These results show an antagonistic effect between AT and ethanol on blood LH levels and suggest a role of brain catalase activity on this effect of ethanol. Data are discussed in terms of a possible functional relationship between brain catalase and beta-endorphins in the mediation of some of the psychopharmacological consequences observed after ethanol administration.
Sanchis-Segura
Carles
C
Area de Psicobiologia, Universitat Jaume I, Campus de Borriol, Apartat. 8029 AP, Castelló 12071, Spain.
Aragon
Carlos M G
CM
D000640:Amitrole / Q000494:pharmacology; D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000201:enzymology*; D002374:Catalase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D000431:Ethanol / Q000037:antagonists & inhibitors / Q000633:toxicity*; D007986:Luteinizing Hormone / Q000037:antagonists & inhibitors* / Q000097:blood* / Q000378:metabolism; D008297:Male; D051379:Mice
D004791:Enzyme Inhibitors; D000431:Ethanol; D007986:Luteinizing Hormone; D002374:Catalase; D000640:Amitrole