The induction of lung tumours by the injection of 9.10-dimethyl-1,2-benzanthracene (dmba) into newborn suckling and young adult mice a dose response study

Abstract

1. Groups of newborn (less than 24 hours old) BALB/c mice were injected. subcutaneously, with 40, 20, 10, 5, 2·5, 1·25 or 0 625, ug. DMBA in 3% aqueous gelatine. A control group received aqueous gelatine only. Lung tumour incidence. multiplicity and size increased with dose, but the tumour/dose relationship was not linear. 0.625 μg. increased the tumour incidence above the control level in males; 2 5 μg. did so in females. 2. 15 μg. DMBA gave rise to a significantly greater incidence of lung tumours when administered to newborn mice (body weight 1.5 g.) than to sucklings (body weight = 6 g.) or young adults (body weight=18 g.). The mean nodule count was higher and size of the largest tumour greater in the neonatally-injected groups. 3. When the dose of DMBA was related to the body weight, i.e. 15 μg. /1 5 g., 60 μg./6 g., or 180 μg./18 g. the newborn mice were only slightly more sensitive than older animals. I am grateful to Dr. F. J. C. Roe for his help and advice and to Miss Maralis Carter and Mrs. Ruth Hickman for their skilled technical assistance. This investigation has been supported by grants to the Chester Beatty Research Institute (Institute of Cancer Research: Royal Cancer Hospital) from the Medical Research Council and the British Empire Cancer Campaign for Research, and by the Public Health Service Research Grant No. CA-03188-08 from the National Cancer Institute, U.S. Public Health Service. © 1966, The British Empire Cancer Campaign for Research. All rights reserved.