Transplacental carcinogenic effect of n-nitrosoethylurea in dogs.

During the late period of pregnancy (on the 50th and 53rd days post coitum) 2 dogs were injected intraperitoneally with 100 mg/kg (a single administration) of nitrosoethylurea. Nine puppies were born. During the 9 year period of observation no tumours were detected in mother-dogs. Three of 9 offspring developed the following tumours: brain haemangioblastoma (on the 526th day after administration), nephroblastoma and spleen angioleiomyoma (on the 845th day after administration) and adenoma of thyroid gland (after 7 years). Among other lesions 3 offspring-dogs developed polycystic kidneys. The revealed tumours of brain, kidney and spleen could be connected with transplacental carcinogenic effect of N-nitrosoethylurea (NEU), while neoplasms of these localizations and types rarely occur in dogs spontaneously.