Influence of dinitroglycerol and nitroethyleueglycol lipid derivatives on spectral parameters of human hemoglobin

The interaction of organic nitrates (nitroethyleneglycol, dinitroglycerol, and their esters with arachidonic acid) with oxyhemoglobin and methemoglobi n has been studied. Addition of nitroethyleneglycol and dinitroglycerol to oxyhemoglobin is accompanied by a modest but significant increase in oxidat ion rate of the heme protein to the high-spin ferri-form-methemoglobin. Ara chidonoylglycerol dinitrate exerts a similar but more pronounced effect on hemoglobin: a molar excess of this dinitrate induces the transformation of a significant portion of oxyhemoglobin to methemoglobin, whereas arachidono ylnitroethyleneglycol is inactive. Arachidonoylglycerol dinitrate also indu ces changes in the spectral characteristics of methemoglobin; this may be d ue to disintegration of the methemoglobin with the loss of heme. The data d emonstrate that some organic nitrates can interact with hemoglobin; this sh ould be taken into account when using the oxyhemoglobin technique for measu ring nitric oxide generation from these compounds.