Abstract

number and size of renal tubular cell tumors in male W rats treated with 500 or 1,000 ppm N-ethyl-N-hydroxyethylnitrosamine [(EHEN) CAS: 13147-25-6, 2-(ethylnitrosamino)ethanolj. At the end of the 32-week experiment, the incidences of renal tumors were 95 % in rats treated with 1,000 ppm EHEN for 2 weeks and then given three sc injections of DL-serine every 2 weeks, 33 % in rats treated with 1,000 ppm EHEN for 2 weeks, and 28 % in rats treated with 500 ppm EHEN for 2 weeks and then given three sc injections of DL-serine every 2 weeks. No renal tumors were found in rats treated with 500 ppm EHEN alone or given three sc injections of DL-serine alone every 2 weeks.-JNCI 1984; 73: 297-299. The development of renal tubular cell tumors in rats treated with EHEN was reported to be promoted by basic lead acetate or {3-cyclodextrin (1-3). Long-term treatment with a high dose of basic lead acetate only also induces renal tubular cell tumors (4-7), whereas {3-cyclodextrin is a nephrotoxic but not a carcinogenic agent (8, 9). The mechanism of the promoting effects of these compounds on renal tubular cell tumorigenesis is still unknown, but one possibility is that since they both induce degenerative lesions of the proximal con-voluted tubules (8-12), these degenerative lesions may be related to their promoting effects on renal tubular cell tumorigenesis (1). DL-Serine also induces degenera-tive lesions of the proximal convoluted tubules (13-23), so in this work we studied the effect of DL-serine on renal tumorigenesis and compared it with the effects of {3-cyclodextrin and basic lead acetate. MATERIALS AND METHODS