RESUMO
28 out of 35 workers exposed to some benzene, phenol and aniline derivatives were found to have high blood methemoglobin levels compared with non-exposed subjects. Methemoglobinemia was mostly accompanied by decreased blood reduced glutathione [GSH] levels. Incubation of fresh blood samples with different concentrations of dichloroaniline [DCA], aniline-HC1. dinitro-chlorobenzene [DNCB] and p-nitrophenol indicated clearly that the first three compounds cause elevation of blood methemoglobin and reduction of GSH. p-Nitrophenol, however, decreases blood inethemoglobin and increases GSH. Blood samples pre-incubated with either DCA or DNCB were incubated with 14C1-glucose and the activity of pentose phosphate pathway [PPP] of glucose oxidation was estimated. The results revealed that low concentrations of both chemicals stimulated the pathway while high concentrations inhibited it. These findings are discussed in the light of the various factors controlling methemoglobin level including NADPH and GSH produced from glucose oxidation through PPP