Effect of ingested lead on concentration of blood and tissue lead in rabbits

The accumulation of lead (Pb) and erythrocyte protoporphyrin (EP) in blood was studied in 11 rabbits. The rabbits were given a daily dose of 50 mg Pb as lead nitrate, dissolved in 100 mL of drinking water. Blood samples were drawn once a week from the ear lobes and assayed for Pb and EP. The Pb concentration increased sharply during the administration of Pb while the EP concentration rose slowly. When Pb was withdrawn its concentration fell immediately, whereas the EP concentration started decreasing only after two weeks and the decrease was slower. At the end of the experiment the rabbits were sacrificed and the Pb content of a number of organs determined. The largest accumulation of Pb was in bone, followed by kidney, liver, lung, spleen, brain and heart. The concentration of Pb in brain and heart was much lower than in the excretory organs - spleen, kidney and liver.