Tissue distribution of lead in rat pups nourished by lead-poisoned mothers.

Lead accumulation was studied in rats treated with Pb through the dam's milk from birth to weaning. Dams of experimental litters received lead acetate in drinking water, while dams of control litters received a sodium solution. Fluid consumption by dams and pup weight were monitored daily. No differences were seen in the dams' fluid consumption or in mortality or growth rate of pups. Rats were sacrificed after 5, 10, 16, or 21 d of Pb treatment, or 3 and 3.5 mo after weaning. Samples of heart, brain, liver, kidney, intestine, and bone were solubilized in concentration nitric acid and analyzed for Pb by atomic absorption spectrophotometry. Nitric acid digests of blood samples from pups 10 and 21 d old and from animals allowed a Pb-free period of 3-3.5 mo after treatment were also analyzed for Pb concentration. Levels of Pb in all tissues analyzed progressively increased during the first 10 d of treatment. After the Pb-free period only bone Pb concentration remained elevated. The results indicate that treatment of lactating dams is an efficient method of producing chronic Pb exposure of rat pups. The results also provide a means of comparing studies of Pb toxicity in which different treatment paradigms are used.