Effects of an initiation-promotion-initiation protocol on the liver carcinogenesis in the one day old rat
Saviozzi, M.; Malvaldi, G.
Bollettino della Societa Italiana di Biologia Sperimentale 63(2): 167-170
1987
ISSN/ISBN: 0037-8771 PMID: 3620179 Document Number: 289292
To investigate whether a further administration of an initiator in a two stage model of liver carcinogenesis increases the incidence of tumors, one day old female Sprague-Dawley rats received an initiating DEN injection. Three weeks later they were placed on a TB promotion regimen and received a second DEN injection before or after this promotion cycle. Rats were killed 3 months later along with suitable controls. Enzyme altered hepatocyte foci were seen in all animal groups; their number, size and morpho-histochemical features being different among them. On the contrary only rats which received the second DEN injection after TB administration showed liver tumors. These results are consistent with the hypothesis that liver carcinogenesis is a multistep process and suggest that addition of a second initiating step shortly after an initiation-promotion protocol may enhance the development of tumors.