Studies on Leukemogenesis in RF Mice by Oral Administration of 20-methylcholanthrene. I. Induction of Leukemia by Oral Administration of 20-methylcholanthrene

1) RF mice were fed three times a week wih 0.1-0.15cc of 0.4 and 0.8% 20-methylcholanthrene in olive oil by means of a needle of a catheter. The mode of development of myelogenous and lymphocytic leukemias in these mice was studied by observation of the peripheral blood picture, histological change and clinical tirsue culture. A fibrosarcoma`and lungadenomas were also observed in a mouse, respectively. 2) Leukemias induced were mainly myelogenous and their incidence was proportional to the concentrations of 20-methylcholanthrene administered. Of mice given 0.4% solutiom of the carcinogen, 17% developed myelogenous leukemia while of mice given 0.8% solution, 50% developed myelogenous and 12.5% lymphocytic leukemia. 3) Histologically all the leukemic mice showed leukemic infiltration in many organs including the bone marrow, spleen, lymph nodes and thymus. Clinical tissue culture of these organs confirmed the diagnosis of leukemia.