ABSTRACT
In former papers we have repoted the existence of a duodenl factor that prevents the developement of Walker's carcinoma when is mixed whith Walker's tumor cells before their inoculation in outbred Sprague- Dawley rats by i.p.,s.c.ori.m.injection. We have also reported, that the duodenal extract (DE) obatined inmediatly after parturition has a stronger inhibitory effect than the duodenal extract from vigin female rats or that of male rats. We have also described some characteristics of the action of the H² Blockers and tyhe sodium-bicarbonate effect.In this paper we are reporting the action of duodenum and colon extracts of rat and duodenum of mouse extract on the transplantable mouse mamary carcinoma (INHRR-984 Ca) originated spontaneouly in outbred N:NIH (S) mouse described elsewhere