The chemistry of the in vivo reaction between haemoglobin and various oxides of nitrogen

Abstract

Massive conversion of oxyhaemoglobin to methaemoglobin has been found in a series of anaesthetized dogs exposed to nitric oxide or nitrogen dioxide in concentrations of 2 per cent, 100 per cent conversion occurring in one case. Less marked changes occurred with inspired concentrations in the range 0.1-0.5 per cent. Reduction in oxygen capacity contributed to the death of some dogs in the series. Almost complete reconversion to oxyhaemoglobin was accomplished with methylene blue. There was no evidence for the formation of other compounds such as nitric oxide-haemoglobin, nitric oxide-methaemoglobin and nitrite-methaemoglobin. © 1967 John Sherratt and Son Ltd.