Formation of methemoglobin by 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone, MX, in rat erythrocytes in vitro.

Oxidative effects of 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), the principal bacterial mutagen in chlorinated drinking water were studied in rat erythrocytes. Upon incubation of rat blood with 14C-labelled MX (2 micrograms/ml), 42% of the radioactivity was found in plasma, 26% in erythrocyte cell membranes and 32% bound in hemoglobin. Although it was bound to hemoglobin, MX (1 mM) did not immediately affect the oxygen binding capacity of hemoglobin. MX (0.5 to 5 mM) decreased the portion of oxyhemoglobin and increased that of methemoglobin in erythrocytes suspended in buffer in a time- and concentration-dependent fashion. In the same concentration range MX did not stimulate proteolysis nor did it cause hemolysis in erythrocytes. The results indicate that MX binds to hemoglobin and stimulates oxidation of hemoglobin in erythrocytes but MX does not cause overt oxidative damage to erythrocytes.