Investigation of methaemoglobin reduction by extracellular NADH in mammalian erythrocytes.

The effect of extracellular NADH on the rate of reduction of nitrite-induced methaemoglobin in erythrocytes from man, cattle, dog, horse, grey kangaroo, pig and sheep was investigated. Extracellular NADH was found to enhance the rate of methaemoglobin reduction in man, dog, pig and kangaroo erythrocytes, but had essentially no effect on the rate of methaemoglobin reduction in erythrocytes from cattle, horse and sheep. In erythrocytes of those animals affected by extracellular NADH the rate of reduction of metHb in the presence of NADH was the same or greater than that observed in the presence of nutrients such as glucose and inosine.

Enhancement of glutathione-dependent haemin degradation by ascorbic acid.

In the current work, we investigated the effect of ascorbic acid on GSH-mediated haemin degradation. GSH-mediated haemin degradation in the presence of ascorbic acid in phosphate-buffered saline and in erythrocyte ghosts was determined by recording absorbance at 365 and 399nm, respectively. Generation of intracellular H(2)O(2) was measured indirectly in terms of the inactivation of endogenous catalase in erythrocytes in the presence of 3-amino-1,2,4-triazole.

Chlorodinitrobenzene-mediated damage in the human erythrocyte membrane leads to haemolysis.

1-chloro-2,4-dinitrobenzene (CDNB), an intracellular glutathione-depleting agent, has been shown to have an adverse effect on erythrocyte membrane integrity. In the current study, we have demonstrated that CDNB caused haemolysis of human red blood cells (RBC) at higher concentrations (>or= 5 mM). The haemolysis induced by CDNB was preceded by the leakage of K(+) from the cells suggesting the colloid-osmotic nature of this lysis.