[Evaluation of the combined effect of lead and sodium nitrite on some blood biochemical parameters in blood of rats during subchronic exposure. Influence on levels of methemoglobin, sulfhydryl groups and tryptophan].

The study was performed on 4 groups of male Wistar rats, receiving p.o. through 3 months every day: 1) distilled. water (control group); 2) sodium nitrite in dose 30 mg/kg b.w. x day (20% LD50); 3) lead acetate in dose 10 mg/kg b.w. x day (6.7% LD50); 4) lead acetate and sodium nitrite in amounts as above. The methemoglobin and hemoglobin were determined in whole blood, tryptophan--in plasma and free sulfhydryl groups--in erythrocytes. There was shown methemoglobin creative effects by nitrite (4.17%) and lead (3.02%) after 90-days intoxication. Both nitrite and lead significantly decrease free sulfhydryl groups and tryptophan levels in blood. There was also observed that lead administrated together with sodium nitrite does not increase methemoglobin concentration.