Changes in fatty acid composition of lipids from birds, rodents, and preschool children exposed to lead |
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Authors: | Scott O Knowles William E Donaldson James E Andrews |
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Institution: | (1) Department of Toxicology, North Carolina State University, 27695 Raleigh, NC;(2) National Health, Environmental Effects Research Laboratory, Reproductive Toxicology Division, 27711 Usepa, RTP, NC;(3) Present address: AgResearch Grasslands, Palmerston North, New Zealand |
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Abstract: | Chronic treatment with inorganic lead (Pb) has been shown to increase the proportion of arachidonic acid (ArA), as well as
the arachidonate/linoleate (ArA/LA) ratio, in the fatty acids of lipids from a variety of avian tissues. Changes in two fatty
acid-mediated phenomena, peroxidation of membrane lipids and synthesis of eicosanoid cytokines, are associated with this enhanced
ArA content. The authors are not aware of any reports in the literature in which these effects of Pb have been described for
any animals other than birds. In the current study, the authors investigated the effect of Pb on lipid metabolism in three
species: avian, rodent, and human. The group of children identified as suffering environmental Pb exposure were from a Pb-surveillance
program and had blood Pb concentrations (PbB) averaging 23 μg/dL. Turkey poults fed 100 ppm dietary Pb as Pb acetate-trihydrate
for 19 d had a PbB of 46 μg/dL. Gastric intubation of rats with 80 mg Pb/kg/d for 10 d resulted in a PbB of 74 μg/dL. We analyzed
fatty acid composition of whole blood from children, poults, and virgin rats. Low-dose (nongrowth inhibitory) Pb exposure
resulted in significantly increased ArA concentration and ArA/LA ratio in blood from all species. Also analyzed were plasma
and liver of poults, virgin rats, and pregnant rats and their fetuses. In plasma and liver from Pb-treated poults and virgin
rats, ArA and the ArA/LA ratio were again enhanced. Pb intoxication also affected ω3 composition, increasing the concentrations
of all long-chain ω3 fatty acids of fetuses from Pb-treated pregnant dams. The authors propose that altered fatty acid metabolism
may be responsible for some indications of Pb poisoning. Possible consequences mediated through lipid peroxidation and production
of ArA-derivative eicosanoids are considered. |
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Keywords: | Arachidonic acid avian blood lead human linoleic acid rodent |
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