TRANSPLACENTAL EFFECTS OF NITROSAMINES IN SYRIAN-HAMSTERS .1. DIBUTYLNITROSAMINE AND NITROSOHEXAMETHYLENEIMINE

The transplacental carcinogenic effects of dibutylnitrosamine (DBN) and nitrosohexamethyleneimine (N-6-MI) were examined in Syrian hamsters. A proportion of both substances reached the fetal tissue unaltered. No macroscopic malformations were observed in the offspring. Postnatal mortality was high. Respiratory tumors were found on histologic examination of surviving animals. Single doses of 30 mg/kg body weight (b.w.) DBN and 2 doses of 10 mg/kg b.w. N-6-MI did not induce tumors in the P[parental]-generation, but led to a low tumor incidence in the F1 generation (DBN, 7.0%; N-6-MI, 2.0%). Treatment up to 8 days during the 2nd half of pregnancy led to a higher tumor incidence in the P generation (DBN, 22%; N-6-MI, 20%), than in the F1 generation (DBN, 6.0%; N-6-MI, 10%).