Changes in organ nonprotein sulfhydryl and glutathione concentrations during acute and chronic administration of inorganic lead to chicks |
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Authors: | Claude McGowan W E Donaldson |
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Institution: | (1) Toxicology Program, North Carolina State University, 27695-7608 Raleigh, NC |
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Abstract: | The effects of dietary and injected lead (Pb) on organ nonprotein sulfhydryl (NPSH) and glutathione (GSH) concentrations in
the chick were studied. Lead acetate·3H2O was administered either in the diet for 3 wk at 2000 ppm Pb or by intraperitoneal (ip) injection of 3-wkold chicks with
52 mg Pb/100 g body wt. In Exp. 1, NPSH concentrations in liver and kidney were increased by both dietary and injected Pb
in comparison to chicks not receiving Pb. Thigh muscle NPSH was decreased by injected Pb, whereas dietary Pb had no effect.
In Expt. 2, whole blood and plasma NPSH were measured at 0, 0.5, 1.0, 2.0, and 4.0 h following ip Pb injection. Both whole
blood and plasma NPSH were increased by 30 min. Whole blood NPSH concentrations plateaued at 30 min, and plasma NPSH continued
to rise for 2 h. In Expt. 3, injected Pb increased hepatic NPSH, but not GSH concentrations. The ratio of GSH/NPSH was therefore
lowered. The incorporation of 1-14C]glycine into hepatic GSH was stimulated by injected Pb. Buthionine sulfoximine (BSO), an inhibitor of GSH synthesis, reduced
hepatic NPSH and 14C]glycine incorporation in Pb-treated chicks to below control (non-Pb injected) values. In Expt. 4, dietary Pb fed for 3 wk
increased the hepatic concentrations of both NPSH and GSH such that the ratio of GSH/NPSH was unchanged in comparison to chicks
not fed Pb. The data suggest that the initial response to acute Pb intoxication may involve a mobilization of nonprotein thiols
via the interorgan translocation system for GSH. Such a response would help to maintain adequate levels of GSH in organs crucial
to detoxification. |
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Keywords: | Nonprotein thiols glutathione lead toxicity buthionine sulfoximine lead dietary and injected effects on an organ nonprotein sulfhydral and glutathione concentrations |
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