Incidence of Preneoplastic Foci in Rat Liver Dependent on Different Promoting Schemes.

After initiation, preneoplastic cell foci emerge in rat liver. They develop differently dependent on promotion, which favors foci incidence with respect to number and size. The process of promotion is dependent on various factors, e.g. the onset and duration of the promotion period (e.g. Deml et al 1981, for literature see: Oesterle and Deml 1983; Deml and Oesterle 1987). In the present experiments, using the rat liver foci bioassay (Oesterle and Deml 1983), the kinetics of development of foci was studied after the application of three different promoting schemes