Benzo(a)pyrene metabolism by lymphocytes from normal individuals and individuals carrying the mediterranean variant of glucose-6-phosphate dehydrogenase
✍ Scribed by F. Feo; M. E. Ruggiu; L. Lenzerini; R. Garcea; L. Daino; S. Frassetto; V. Addis; L. Gaspa; R. Pascale
- Publisher
- John Wiley and Sons
- Year
- 1987
- Tongue
- French
- Weight
- 617 KB
- Volume
- 39
- Category
- Article
- ISSN
- 0020-7136
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✦ Synopsis
In vitro growing human lymphocytes (HL) and fibroblasts, isolated from glucose-6-phosphate dehydrogenase (G6PD)-deficient subjects (Mediterranean variant), show a sharp decrease in this enzymatic activity and in NADPH:NADP+ ratio. These cells are less able than controls to hydroxylate benzo(a)pyrene (BaP) when tested in the absence of an exogenous NADPH-generating system. They exhibit great resistance to the toxic effect of BaP. G6PD-deficient fibroblasts are less prone than controls to in vitro transformation by BaP. To investigate whether this depends on a decreased production of active BaP metabolites and BaP:DNA adducts by G6PD-deficient cells, BaP metabolism was studied in G6PD-deficient HL cultured in vitro in the presence of mitogens and treated with BaP for 24 hr. HPLC profiles of organo- and water-soluble metabolites revealed that both types of benzo(a)anthracene (BaA)-induced HL produced: 4,5-, 7,8-, 9,10-diols, 1,3-, 3,6-quinones, 3-, 9-hydroxy and 2 peaks of more polar metabolites. There was a 25-76% decrease of organo- and water-soluble metabolites in the G6PD-deficient cells. When HL were incubated with 7,8-diol, the formation of metabolites mutagenic for Salmonella typhimurium (His-) was very low in G6PD-deficient cells. BaP:deoxyadenosine (dAde) and BaP:deoxyguanosine (dGua) adducts were identified after incubation of both types of HL with BaP. There was a 31-79% fall in adduct formation by G6PD-deficient cells. Our results indicate that G6PD-deficient human lymphocytes are less able to metabolize BaP than normal lymphocytes. We suggest that the NADPH pool is inadequate, in deficient cells, for active BaP metabolism.