Influence of dietary protein deficiency on lead-copper interaction in rats

The influence of dietary protein deficiency on the effects of exposure to lead or its combination with copper was investigated in rats. The administration of lead (100 ppm in drinking water) inhibited the activity of blood delta-aminolevulinic acid dehydratase; decreased hemoglobin, brain dopamine, and 5-hydroxytryptamine; and increased urinary excretion of delta-aminolevulinic acid, blood zinc protoporphyrin, and tissue accumulation of lead more markedly in animals fed a protein-deficient diet (10% casein) than in those fed a normal diet (21% casein). The simultaneous supplementation of copper (100 ppm in diet) reduced some of the lead-induced alterations and body uptake of lead more efficiently in animals fed a normal diet than in those fed a protein-deficient diet, which shows that the beneficial effects of copper in lead toxicity are adversely affected by low dietary protein.