Effects of lead and cadmium on adrenal and thyroid functions in rats.

Seventy sexually mature male rats were injected with lead (50 and 250 mcg), cadmium, (50 and 250 mcg) and a mixture of lead (25 mcg) and cadmium (25 mcg) for 70 days. TSR results show that 250 mcg cadmium had a stimulating effect but 1/10 of the dose of cadmium plus 25 mcg lead had the opposite effect. Plasma thyroid hormones indicated that 50 mcg lead had a stimulating effect on T4 but cadmium and a mixture of lead and cadmium had a suppressing effect on both T4 and T3. Plasma corticosterone and adrenal cortical histology showed increased adrenal function in animals treated with 50 mcg lead, 50 mcg and 250 mcg cadmium and a mixture of lead and cadmium. The data indicated that cadmium had more deleterious effects on thyroid and adrenal function than lead.