Adaptation to the Toxic Effects of Lead

Adaptation to the toxic effects of lead, mercury, and cadmium has been reported by several investigators. In this study, we examined the susceptibility of male white albino mice to lead toxicity after pretreaitment with a small intraperitoneal dose of lead nitrate. Indices of lead toxicity chosen for study were lethality, body weight loss, liver and kidney weight changes, hematocrilt, and inhibition of liver δ-aminolevulinic acid dehydratase activity. Pretreatment with lead nitrate (10 or 20 mg/kg i.p.) protected mice against the acute lethal effects of a 200-mg/kg i.p. dose of lead nitrate, the optimal time of pretreatment being 4 days before the challenge dose. Pretreatment with lead nitrate (20 mg/kg i.p) did not attenuate and may have exacerbated the subacute lead toxicity Induced by a 4% basic lead carbonate diet fed over a 12-day period. It appears that only selected biological parameters develop resistance to lead.