Effects of N-Methyl-N’-Nitro-N-nitrosoguanidine and deoxycholic acid on processes of tumorous transformation of rat visceral yolk sac: In vitro and in vivo Studies

The possibility to use the rat visceral yolk sac as a model for the study of processes of ceil transformation was studied. Yolk sac teratocarcinomas could be induced using the method of in vitro culture of yolk sacs in a medium containing a direct carcinogen and a tumor promoter with subsequent transplantation under the renal or testicular cap sule of syngeneic rats. Biochemical, electron-microscopic and immunohistochemical methods were used to study the characteristic changes that accompanied cellular transformation. It was shown that even a short-term (3 h) exposure of the yolk sac celis lo N-methyl-N'-nitro-N-nitrosoguanidine with or without deoxycholic acid in vitro decreased signif icantly the rate of yolk sac transport and changed their developmental potential with manifestation of carcinogenic anti gens (polyclona! keratins, monoclonal vimentin and smooth muscle aclin). This cancerous transformation was pro moted following their in vivo transplantation into special anatomic sites.