Certain agents precipitate oxidant damage and hemolysis of glucose-6-phosphate dehydrogenase (G6PD) deficient erythrocytes. Both hydrogen peroxide (H(,2)O(,2)) and drug metabolites have been implicated as the oxidants produced by these agents. The influence of extraerythrocytic factors on transforming these agents into oxidants has never been elucidated. Promizole, however, only hemolyzes the G6PD-deficient cells of some individuals, indicating that hemolysis requires the enzyme deficiency, the drug, and some other unknown factor(s). This thesis examines the initiation of damage to G6PD-deficient cells by both the products of oxygen (O(,2)) reduction and promizole metabolism. Products of O(,2) reduction. In vitro, two known hemolytic drugs, menadione and acetylphenylhydrazine, were shown to produce superoxide (O(,2)('-)). Red blood cells were then exposed to O(,2)('-), H(,2)O(,2), and hydroxyl radical generated during the oxidation of xanthine (X) by xanthine oxidase (XO). Glutathione (GSH) oxidation occurred only in G6PD-deficient cells so exposed; methemoglobin formation and Heinz body production were markedly increased in deficient cells compared to normals. These effects were secondary to H(,2)O(,2). Superoxide contributed to the rate of H(,2)O(,2) formation. Products of promizole metabolism. Methemoglobin and GSH were measured in erythrocytes exposed, in vitro, to promizole and acetylpromizole in the presence or absence of liver microsomes. No GSH oxidation was observed in erythrocytes exposed to either drug alone; however, in G6PD-deficient cells, the acetylated drug produced less GSH oxidation than promizole in the presence of induced liver microsomes. This was partially inhibited by a cytochrome P-450 inhibitor. Acetylation produced a similar protective effect on methemoglobin production. To examine this in vivo, we unsuccessfully attempted to produce a model for G6PD deficiency using BCNU to inhibit glutathione reductase (GR) in rabbits with the acetylation polymorphism. Drugs known to be hemolytic to G6PD-deficient cells did not produce hemolysis of these GR-inhibited cells. This work suggests that G6PD deficiency is a necessary condition for hemolysis to occur with certain drugs, but that extraerythrocytic factors such as drug acetylation and hydroxylation can influence the hemolytic potential of a drug. Hydrogen peroxide was the only product of oxygen reduction examined that was found to have a role in initiating damage to G6PD-deficient cells.Ph.D.GeneticsUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/158485/1/8125155.pdf