Effects of ethylnitrosourea administration during pregnancy on three subsequent generations of BDVI Rats.

A single dose of 40 mg/kg of N-nitrosoethylurea (ENU) was administered to BDVI rats on the 16th day of pregnancy. The first generation descendants (F1) were mated on a brother-to-sister system to produce a second generation (F2) which was then mated to produce a third generation. A high incidence of nervous tissue tumors and a few kidney tumours were observed in F1 descendants. A few nervous tissue tumours were observed in F3 but not in F2 descendants. These results partially confirm previous observations obtained with 7,12-dimethylbenz(a)anthracene in mice and nitrosomethylurea in rats and indicate that prenatal exposure to a chemical carcinogen may result in an increased cancer risk which can persist for more than one generation.