[Role of age in N-nitrosodimethylamine- and N-dimethylnitramine-induced carcinogenesis in Rana temporaria L. amphibians].

A comparison of the reactions of adult and juvenile amphibians Rana temporaria showed that the host sensitivity (latency and tumour incidence) of both groups of animals to the carcinogenic action of N-nitrosodimethylamine and dimethylnitramine was of the same order. However, a "shift" in organ sensitivity (different organotropic effect) was observed. The predominance of hepatocellular cancer in adult and hemocytoblastosis in young Rana temporaria was significant (P less than 0,01). The mechanisms of these "shifts" are unknown, but a role of the metabolic and reparative processes has been suggested.