Studies on Distribution and Excretion of Lead in Rat after Administration of Lead Compounds

Lead nitrate (80mg/kg Pb), lead stearate (80mg/kg Pb), and tetraethyl lead (0.3mg/kg Pb) were given to 3 separate groups of rats by a single oral administration. Difference in the distribution and excretion of lead in rats among these 3 kinds of lead compounds was examined. Atomic absorption spectrophotometry was used for the determination of lead in biological materials. After administration of lead nitrate, 92% of lead administered was excreted in the feces within 3 days. The highest distribution of lead was found in the liver (0.169±0.030%), followed by the kidney (0.153±0.018%), leg bone (0.078±0.015%), blood (0.052±0.015%), and rib (0.023±0.006%) at 7 hr after the administration. Lead distributed in the liver, kidney, and blood decreased rapidly, while that in the leg bone and rib increased up to 2 days after the administration, and then decreased slowly. After administration of lead stearate, distribution and excretion of lead were similar to those of lead nitrate. In the case of tetraethyl lead, 62% of lead was excreted in the feces during 8 days. The highest lead distribution was found in the liver throughout the experiment (27.1±3.5% after 7 hr and 12.5±3.4% after 32 days). Lead distributed in the blood, kidney, brain, leg bone, and rib increased up to 3 or 4 days after the administration. On the 32 nd day, lead in the blood and rib was almost 0%, but lead was found in the kidney (1.29±0.39%), brain (0.75±0.36%), and leg bone (3.13±1.35%).