Methionine synthase activities in mice following acute exposures to ethanol and nitrous oxide.
Acute or chronic exposure to nitrous oxide or chronic exposure to ethanol decreases the activity of the vitamin B12-dependent enzyme methionine synthase. To assess the combined effect of acute exposure to nitrous oxide and ethanol, mice were given an intraperitoneal injection of ethanol (3 g/kg) and exposed to an inspired mixture of 66% nitrous oxide and 34% oxygen for 4 hr. Methionine synthase activities in liver, kidney, and brain were measured immediately after exposure to nitrous oxide and at various times over a 4-day recovery period. Methionine synthase activities in liver and kidney returned to control levels 2-4 days following inactivation. In brain, a significant 16% decrease in methionine synthase activity remained after a 4-day recovery period. The acute administration of ethanol did not alter the magnitude of the inactivation induced by nitrous oxide nor the time course of recovery of methionine synthase activity following inactivation. Moreover, in mice that were not exposed to nitrous oxide, methionine synthase activity was not altered by the acute administration of ethanol alone or in combination with 0.4% atm isoflurane. Thus, in this animal model, an acute dose of ethanol does not alter methionine synthase activity nor does it enhance the inactivation produced by nitrous oxide.
Koblin
D D
DD
Department of Anesthesia, University of California, San Francisco 94143.
Tomerson
B W
BW
D013766:5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase / Q000037:antagonists & inhibitors*; D000818:Animals; D001921:Brain / Q000201:enzymology; D004347:Drug Interactions; D000431:Ethanol / Q000494:pharmacology*; D007530:Isoflurane / Q000494:pharmacology; D007668:Kidney / Q000201:enzymology; D008099:Liver / Q000201:enzymology; D008297:Male; D008780:Methyltransferases / Q000037:antagonists & inhibitors*; D051379:Mice; D008813:Mice, Inbred ICR; D009609:Nitrous Oxide / Q000494:pharmacology*
D000431:Ethanol; D007530:Isoflurane; D008780:Methyltransferases; D013766:5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase; D009609:Nitrous Oxide