Transplacental effects of ethylnitrosourea precursors ethylurea and sodium nitrite in hamsters

Age- and dose-dependent transplacental carcinogenesis by N-nitrosoethylurea in Syrian golden hamsters

Syrian golden hamsters have a very short period (15 days) of gestation. The implantation of the blastocyst occurs on day 5, embryogenesis proceeds very rapidly thereafter and neural tube closure is completed by day 9. In the present study the effects of two different doses of N-nitrosoethylurea (NEU) administered at various stages of gestation were quantitatively evaluated in Syrian golden hamsters. NEU at either 0.2 or 0.5 mmol/kg was administered transplacentally as a single i.p. injection to pregnant hamsters on gestation days 7, 8, 9, 10, 11, 12, 13, or 14. The incidence, latency period and multiplicity of tumors varied with the dose of NEU and the stage of development at the time of NEU administration. Although tumors of the peripheral nervous system predominated, a variety of other tumors, including melanomas and visceral tumors of epithelial and mesenchymal origin, were also observed in hamster offspring exposed transplacentally to NEU. Sensitivity to transplacental carcinogenesis was maximal during late gestation and very low before day 9.

Ganglioneuromas in hamsters

A description is given of three cases of ganglioneuromas, which originated from ganglia of the sympathetic chain of hamsters. Other reports of such tumors in this species are reviewed and the literature relative to hamster ganglioneuromas presented. In addition, the possible genesis of origin from adult ganglion cells upon the action of carcinogenic stimuli is discussed.