Effect on blood, liver, and kidney variables of age and of dosing rats with lead acetate orally or via the drinking water

Levels of lead in the livers and kidneys of rats increased in proportion to the dose of lead acetate that the rats were given orally or in the drinking water. The activities of delta-aminolevulinic acid dehydratase (DALAD) in blood and liver decreased when the rats were dosed with lead, whereas glutathione levels in the blood increased. The decrease in the activity of blood DALAD was the most sensitive indicator of lead toxicity. Levels of lead in the livers and kidneys decreased after 3, 7, and 14 d of lead withdrawal. The activities of blood DALAD increased after 3 d of lead withdrawal. Groups of rats that initially weighted an average of 140 g were killed at weekly intervals for 6 wk. Blood hematocrits and liver glutathione levels increased, and blood DALAD and activated DALAD from blood decreased with increasing age of the rats. Activated DALAD activities from liver increased after the first week of the study.