Basic lead acetate: promoting effect on the development of renal tubular cell tumors in rats treated with N-ethyl-N-hydroxyethylnitrosamine.

The development of renal tubular cell tumors by the end of experimental week 32 was studied in inbred Wistar male rats fed a diet containing 1,000 or 500 ppm N-ethyl-N-hydroxyethylnitrosamine (EHEN) for 2 weeks and then given 1,00 ppm basic lead acetate (LA) for 20 weeks. A low dose of LA enhanced the development of renal tubular cell tumors in rats treated with EHEN and increased the number and size of the tumors. The incidence of renal tubular cell tumors at the end of week 32 was 50% in rats treated with 1,000 ppm EHEN for 2 weeks and 100% in rats treated with 1,000 ppm EHEN for 2 weeks and then given 1,000 ppm LA for 20 weeks. The incidences of renal tumors of more than 3 mm in diameter were 70% in rats treated with 1,000 ppm EHEN plus LA and 0% in rats treated with EHEN or LA alone. The low dose of LA showed the enhancing effect of the development of renal tubular cell tumors in rats treated with a subthreshold dose of 500 ppm EHEN.