Subchronic oral toxicity of triethyl lead in the male weanling rat. Clinical, biochemical, hematological, and histopathological effects

This study was designed to ascertain the effects of low level exposure of triethyl lead (3EL) to the male weanling rat. Groups of 20 animals were administered by gavage 3EL at 0.05, 0.10, 0.20, 0.50, and 1.00 mg/kg body wt for 91 days, 5 days/week. Lead acetate (PbHOAC) at 200 mg/kg body wt/day was given as a positive control. Weight gain was reduced in those animals receiving 1.0 3EL. Spleen and kidney weights were elevated in the PbHOAC group. Residues of 3EL and its metabolites diethyl lead (2EL) and lead (Pb) accumulated in a dose-dependent manner in blood, liver, kidney, and brain; 3EL accumulated preferentially in the liver while inorganic lead accumulated in the kidney. Dose-dependent changes occurred in serum calcium which was decreased and in phosphorus which was elevated for all dose groups. Serum cholesterol was elevated in the three highest 3EL groups as was alkaline phosphatase. LDH was lowered in the PbHOAC-treated group but microsomal aniline hydroxylase was elevated. Hematological changes consisted of elevated platelet ccunts in the 1.0 3EL group and decreased mean corpuscular hemoglobin content and mean corpuscular volume in the PbHOAC-treated group. Treatment related histopathological changes were seen in thyroid, liver, kidney, and bone marrow. Based on these data a no observed adverse effect level for 3EL was set at 0.10 mg/kg/body wt.