http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
initial evaluation of the relationship between lead and glutathione in cultured astroglia
xvi, 161 leaves : illustrations ; 28 cm.
The present studies were undertaken to examine the following hypotheses: (1) that cultured astroglia, and not neurons, have an intrinsic ability to accumulate lead (1%), and that this ability is modulated by interaction with other cell types in the central nervous system (CNS); (2) that extracellular and intercellular glutathione (GSH) levels modulate astroglial Pb accumulation in culture; and (3) that GSH levels in the brain modulate Pb accumulation by this organ in the developing rat pup. The results provided some new and interesting Endings. First, immature astroglia in culture were found to accumulate more Pb than did mature cells. Second, immature astroglia were found to accumulate up to 14 times more Pb than did cultured neuronal cells. In addition, this astroglial property of Pb accrual was enhanced when cells were grown in the presence of neuronal-conditioned medium, indicating that this property is specifically inducible by neurons. Third, the presence of GSH in the culture medium not only reduced Pb accumulation by immature astroglia, but also enhanced intercellular GSH levels. Fourth, if intercellular GSH levels were depleted, immature astroglia accumulated more Pb than did not-depleted cells. Fifth, conditioned medium from neuronal cells also reduced astroglial GSH levels. Therefore, the neuronal induction of increased astroglial Pb accumulation may be either through the release of differentiating factor(s) into the medium that regulate astroglial Pb uptake/retention mechanisms, or through modulation of astroglial GSH levels, which may be either through a differentiating elect or through alteration of glutamate and cyst(e)ine levels in the medium. Finally, brain Pb levels in GSH-treated rat pups were lower than those of saline-treated controls. However, depletion of brain GSH levels did not enhance Pb accumulation by this organ, in contrast to the findings in GSH-depleted astroglia. Therefore, in both animal and cell culture studies, treatment with GSH provided some benefit to reducing Pb accumulation in whole brain and astroglia, respectively. Future studies will be needed to elucidate the mechanisms of astroglial Pb uptake as well as Pb export, and the role that GSH may play in each.
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Includes bibliographical references (leaves 139-159).