CHANGES IN FATTY-ACID COMPOSITION OF LIPIDS FROM BIRDS, RODENTS, AND PRESCHOOL-CHILDREN EXPOSED TO LEAD

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, peroxi dation of membrane lipids and synthesis of eicosanoid cytokines, are a ssociated 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 spe cies: avian, rodent, and human. The group of children identified as su ffering environmental Pb exposure were from a Pb-surveillance program and had blood Pb concentrations (PbB) averaging 23 mu g/dL. Turkey pou lts fed 100 ppm dietary Pb as Pb acetate-trihydrate for 19 d had a PbB of 46 mu g/dL. Gastric intubation of rats with 80 mg Pb/kg/d for 10 d resulted in a PbB of 74 mu g/dL. We analyzed fatty acid composition o f whole blood from children, poults, and virgin rats. Low-dose (nongro wth inhibitory) Pb exposure resulted in significantly increased ArA co ncentration and ArA/LA ratio in blood from all species. Also analyzed were plasma and liver of poults, virgin rats, and pregnant rats and th eir fetuses. In plasma and liver from Pb-treated poults and virgin rat s, ArA and the ArA/LA ratio were again enhanced. Pb intoxication also affected omega 3 composition, increasing the concentrations of all lon g-chain omega 3 fatty acids of fetuses from Pb-treated pregnant darns. The authors propose that altered fatty acid metabolism may be respons ible for some indications of Pb poisoning. Possible consequences media ted through lipid peroxidation and production of ArA-derivative eicosa noids are considered.