Abstract

A variety of arylamine derivatives (e.g. dapsone, primaquine) are known to produce hemolytic anemia in man and experimental animals. Extensive studies in the 1950’s and 60’s established that hemolytic drugs induced methemoglobinemia and loss of erythrocytic reduced glutathione (GSH), and that individuals deficient in erthrocytic glucose-6-phosphate dehydrog-enase displayed enhanced susceptibility to drug-induced hemolytic anemia (for review, see E. Beutler, 1969; E. Beutler, 1972). Since drugs such as primaquine were active in vivo but not in vitro, the concept arose that the drugs were metabolized in the liver to active/reactive metabolites which, on entry to the red cell, produced a state of “oxidative stress”. The resulting oxidative damage to critical sites within the red cell has been considered to lead to their “premature aging” and premature removal from the circulation by the spleen (A.R. Tarlov, et al., 1962; F.C. Gooden-Smith, et al., 1974; G. Cohen et al., 1964; A. Miller et al., 1970; R.W. Carrell, et al., 1975). The nature of the oxidant stress and the identity of the critical sites, however, are still unclear. Since the oxidation of hemoglobin to methemoglobin is known to be associated with the reduction of oxygen, much work has centered around the role of active oxygen species and free radicals as molecules capable of attacking cellular components (G. Cohen, et al., 1964; R.W. Carrell, et al., 1975; H.P. Misra et al., 1976; H.A. Itano, et al., 1977; B. Goldberg, et al., 1977). We have recently shown that phenylhydroxylamine (PHA) is a direct acting hemotoxin, capable of damaging the red blood cell during in vitro incubation such that, when readministered to isologous rats, the cells are rapidly sequestered by the spleen (J.H. Harrison, et al., 1986). This communication describes spin trap studies aimed at determination of whether or not free radical specie(s) are formed in the red cell in response to PHA, and if so, the identification of these specie(s).

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