Control of Glucose-6-Phosphate Dehydrogenase Deficiency on the Formation of Mutagenic and Carcinogenic Metabolites Derived from Benzo(a)pyrene (original) (raw)

1987, Toxicologic Pathology

It has been observed that human lymphocytes (HL) and fibroblasts, isolated irt vitro from donors carrying the Mediterranean variant of glucose-6-phosphate dehydrogenase (G6PD), show a great decrease in this enzymaticactivity, the hexose monophosphate shunt, and the NADPHINADP' ratio. This effect is associated with a decreased sensitivity of G6PD-deficient cells to the benzo(a)pyrene (BaP) cytotoxic effect and to a decreased iri vitro transformation of BaP-treated fibroblasts. Further, benzo(a)anthracene (BaA)-induced BaP hydroxylase activity is lower in G6PD-deficient cells, when measured in the presence of endogenous NADPH. It has been hypothesized that the NADPH level could be rate-limiting for the NADPH-dependent steps of BaP metabolic activation. To test this hypothesis, the formation of BaP metabolites was studied in normal and G6PD-deficient HL incubated with the carcinogen. HPLC profiles of organic-soluble metabolites revealed that both types of HL produced all the following known BaP metabolites: 9,lO-, 4,5and 7,8-dihydrodiols, quinones, 9and 3-hydroxy and two peaks of more polar metabolites. There was a great decrease of the various metabolites in the deficient HL. A decrease of total water-soluble BaP metabolites also occurred.