OXIDATION OF INTRACELLULAR GLUTATHIONE AFTER EXPOSURE OF HUMAN RED-BLOOD-CELLS TO HYPOCHLOROUS ACID

Exposure of human red blood cells to low doses of hypochlorous acid (H OCl) resulted in the loss of intracellular GSH. Oxidation occurred les s than 2 min after the addition of HOCl, and required approx. 2.5 mol of HOCl per mol of GSH lost. Loss of GSH preceded oxidation of membran e thiols, the formation of chloramines and haemoglobin oxidation. The susceptibility of intracellular GSH to oxidation by HOCl was two-third s that of GSH in cell lysates. These results indicate that HOCl can pe netrate the red cell membrane, which provides little barrier protectio n for cytoplasmic components, and that GSH oxidation by HOCl may be a highly selective process. Virtually all of the GSH lost was converted into GSSG. If glucose was added to the medium, most of the GSH oxidize d by low doses of HOCl was rapidly regenerated. At higher doses, recov ery was less efficient. However, when HOCl was added as a slow infusio n rather than in a single bolus, there was increased recovery at highe r doses. This indicates that in metabolically active cells regeneratio n is rapid and GSH may protect cell components from damage by HOCl. HO Cl-induced lysis was only slightly delayed by adding glucose to the me dium, indicating that lytic injury is not ameliorated by GSH.