METHEMOGLOBIN FORMATION DUE TO NITRITE, DISULFIRAM, 4-AMINOPHENOL ANDMONOACETYLDAPSONE HYDROXYLAMINE IN DIABETIC AND NONDIABETIC HUMAN ERYTHROCYTES IN-VITRO

Nitrite, monoacetyl dapsone hydroxylamine, 4-aminophenol and disulfira m-mediated methaemoglobin formation was studied in human diabetic and non-diabetic erythrocytes in vitro. Diabetic intact erythrocytes were significantly less sensitive compared with those of non-diabetics to h aemoglobin oxidation caused by the hydroxylamine, nitrite and 4-aminap henol, but not disulfiram. In haemolysates, differential sensitivity d id occur with disulfram and was partially retained with 4-aminophenol and nitrite. The differences were lost with 4-aminophenol, nitrite and disulfiram in the presence of haemoglobin purified from the respectiv e erythrocyte types. Diethyl maleate reduced methaemoglobin formation in non-diabetic intact erythrocytes with 4-aminophenol, the hydroxylam ine and disulfiram, but not with nitrite. Overall, the differential se nsitivity to methaemoglobin formation seen in diabetic compared with n on-diabetic erythrocytes, is probably linked to differences in the res pective cells' cytosolic anti-oxidant systems. (C) 1998 Elsevier Scien ce B.V.