The effects of dietary lead content and food restriction on lead retention in rats

The effects of restricted food intake and of various dietary lead contents on lead retention¹ were studied in young rats. In three experiments the rats were given either unrestricted or restricted access to diets providing 200 or 400 mg lead/kg for 3 or 6 weeks. At the end of the experiments a sample of blood was taken and the rats were ashed. Lead was determined in blood and ash from the carcass. Food restriction always increased the retention of lead but not always the lead content of blood or carcass. The retention of lead was similar when the diet was supplemented with 50, 200 or 400 mg lead/kg. Lead supplementation at 200 or 400 mg/kg reduced food intake and growth but did not affect food conversion ratios. Blood lead was related to the rate of ingestion of lead. The effect of food restriction in reducing lead retention should be taken into account in interpreting the effects of lead exposure accompanied by dietary conditions which reduce appetite or food supply.