Carcinogenic effect of N-nitrosobis (2-oxopropyl)amine in newborn rats.

N-nitrosobis(2-oxopropyl)amine (BOP) was administered twice weekly for a total of 11 doses to 2-day-old Fischer F-344 rats of both sexes to ascertain the spectrum of tissues sensitive to its carcinogenic effects. At 26 weeks, the following incidence of neoplasms were encountered in male and females, respectively; hepatocellular carcinoma (53 and 46%); nephroblastoma (21 and 11%); and in males gonadal stromal tumors of testis (68%). Although acidophilic and basophilic acinar cell foci were encountered in pancreas, these were few in number and microscopic. These findings indicate that in newborn Fischer rats, hepatocytes, epithelial and mesenchymal cells of the kidney, and mesenchymal cells of testis are more sensitive to BOP than those of exocrine pancreas.