Methemoglobin reductase activity and in vitro sensitivity towards oxidant induced methemoglobinemia in swiss mice and beagle dogs erythrocytes.

The NADH methemoglobin-reductase (EC 1.6.2.2) is mainly responsible for the maintenance of hemoglobin in its reduced and active state. The present study reveals the comparative status of this enzyme in normal Beagle dogs, rats, mice, mastomys and hamsters erythrocytes. The spectrophotometric and electrophoretic determinations showed that the above mentioned enzyme was deficient in the Beagle dog's erythrocytes. Furthermore, in vitro studies on the sensitivity of these rodents and Beagle dogs hemolysate towards oxidants, like primaquine and sodium nitrate, depicted a higher level of methemoglobin formation in the Beagle dogs hemolysate as compared to that of the rodent species. The deficiency of methemoglobin reductase in Beagle dogs erythrocytes could be responsible for their increased sensitivity towards oxidant induced methemoglobinemia.