Study on the Binding of Lead and Calcium in the Liver Nuclear of Rats intoxicated with Lead Acetate

Abstract

Following a study on the deposition of calcium in the liver of rats intoxicated with lead reported previously, calcium distribution in organ and liver cell fractions of rats was investigated after a single intraperitoneal administration of lead (0.2 mg/g body wt.). The amount of calcium deposition induced with lead, 3 days after the administration of lead, was highest in the liver, followed by spleen, kidney, heart, and brain in that order, and it was also highest in the liver 30 days after injection of lead. Liver subcellular fraction, obtained from rats 7 days after a single intraperitoneal administration of lead, showed about 65% to 50% lead and calcium associated with nuclear fraction. Lead and calcium associated with the nucleus are removed as a function of hydrogen ion concentration and temperature ; 50% of lead and calcium is removed in the range of pH 3.5, and 25% of lead and calcium is removed by heating to 70° On the other hand, calcium bound to nucleus is removed by 10 mM sodium citrate, whereas lead is not removed, but both lead and calcium are removed by 10 mM Na₂-EDTA. These evidences show that lead and calcium in the liver of rats intoxicated with lead, are bound firmly to the nucleus co-deposited with protein complexes.