EFFECT OF NEUTRONS ALONE OR COMBINED WITH DIETHYLNITROSAMINE ON TUMOR-INDUCTION IN THE LIVERS OF INFANT C57BL MICE

The possible combined effects of the initiator diethylnitrosamine (DFN ) + neutrons on the induction of foci, adenomas and carcinomas in the livers of C57BL/Cnb mice were evaluated. Four groups of infant mice we re treated as follows: DEN alone, neutrons alone, DEN followed by neut rons and neutrons followed by DEN. Ten mice in each group were killed at 10-week intervals over 70 weeks. The following parameters were meas ured: body weight, liver weight, number and size of superficial macros copic liver lesions, and number and total surface area of the differen t types of microscopic liver lesions. The rate of appearance of foci i ncreased significantly at different times when a dose of 0.125 Gy of n eutrons was administered 7 days before or after a dose of 1.25 mu g of DEN. No significant differences were observed in the total surface ar ea of foci and/or adenomas and carcinomas when increasing doses of neu trons were given 7 days before or after the administration of 1.25 and 2.5 mu g of DEN. (C) 1995 by Radiation Research Society