INHIBITORY EFFECT OF CYSTEINE AND METHIONINE ON FREE-RADICALS INDUCEDBY MERCURY IN RED-BLOOD-CELLS OF PATIENTS UNDERGOING HEMODIALYSIS

The inhibitory effects of cysteine and methionine on mercury-induced f ree radicals were studied in the red blood cells (RBC) of haemodialyse d (HD) patients, using polyacrylonitrile membranes. RBC were taken fro m a control group of 10 healthy subjects and a group of 30 HD patients . The following were determined before and after HD: malonyldialdehyde (MDA), total glutathione (GST), reduced (GSH) and oxidized (GSSG) glu tathione, and percentage haemolysis (before HD). RBC were incubated fo r 6 hr with mercury (Hg2+; 10(-5) M), mercury and cysteine (0.001 M) a nd mercury and methionine (0.005 M). The percentage of mercury induced haemolysis differed between the control group and HD patients. The ad dition of cysteine and methionine to RBC has a markedly inhibitory eff ect on the mercury-induced haemolysis (a reduction from about 80 to 5% for cysteine and to 15% for methionine). MDA was increased in HD pati ents and increased further after HD. GST, GSH and GSSG were lower than normal in HD patients, both before and after HD. There was very littl e change in MDA concentration when the RBC were incubated with mercury for 6 hr.