title: Inhibition of dopamine beta-hydroxylase by 4-hydroxypyrazole: ethanol-pyrazole effects on serum dopamine beta-hydroxylase in vivo.
abstract: Chronic pyrazole treatment caused a 40% decrease in rat serum dopamine beta-hydroxylase (DBH) activity. Ethanol given simultaneously with pyrazole prevented the inhibition. 4-Hydroxypyrazole, the major metabolite of pyrazole, competitively inhibited both rat serum DBH and partially purified bovine adrenal DBH in vitro. In vivo, 4-hydroxypyrazole caused large decreases in rat serum (53-84%) and adrenal (97%) DBH activity but had no effect on brain enzyme. The decrease in rat serum DBH after chronic pyrazole treatment and the pyrazole-induced changes in physiological parameters, such as body weight and temperature, may be due to the formation of 4-hydroxypyrazole.
mesh_terms: D000311:Adrenal Glands / Q000187:drug effects / Q000201:enzymology; D000818:Animals; D002417:Cattle; D004299:Dopamine beta-Hydroxylase / Q000037:antagonists & inhibitors* / Q000097:blood; D000431:Ethanol / Q000494:pharmacology*; D006900:Hydroxylation; D066298:In Vitro Techniques; D008297:Male; D011720:Pyrazoles / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D051381:Rats
chemical_list: D011720:Pyrazoles; D000431:Ethanol; D004299:Dopamine beta-Hydroxylase