Synergistic effect of radiation on colon carcinogenesis induced by methylazoxymethanol acetate in ACI/N rats.
The effect on colon and liver carcinogenicity in rats of a single X-irradiation exposure given either before or after methylazoxymethanol (MAM) acetate was studied in ACI/N rats of both sexes. A single dose of X-irradiation (3 Gy) was administered either 3 months before or after three weekly s.c. injections of MAM acetate (25 mg/kg body weight). At 365 days after the start, the incidence and multiplicity of MAM acetate-induced intestinal tumors were enhanced by X-irradiation either prior to or after the MAM acetate treatment. In addition, X-irradiation before MAM acetate increased the incidence of hepatocellular foci in either sex. In females, X-irradiation either before or after MAM acetate exposure decreased intestinal tumorigenesis. These findings suggest an apparent synergism of these agents in intestinal carcinogenesis of male rats.
Tanaka
T
T
First Department of Pathology, Gifu University School of Medicine.
Morishita
Y
Y
Kawamori
T
T
Suzui
M
M
Kojima
T
T
Sugie
S
S
Mori
H
H
D000818:Animals; D001835:Body Weight / Q000187:drug effects / Q000528:radiation effects; D003043:Cocarcinogenesis; D003110:Colonic Neoplasms / Q000139:chemically induced*; D005260:Female; D008099:Liver / Q000187:drug effects / Q000473:pathology / Q000528:radiation effects; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced*; D008297:Male; D008746:Methylazoxymethanol Acetate / Q000031:analogs & derivatives*; D009381:Neoplasms, Radiation-Induced; D009929:Organ Size / Q000187:drug effects / Q000528:radiation effects; D051381:Rats; D011912:Rats, Inbred ACI
D008746:Methylazoxymethanol Acetate; C030667:methylazoxymethanol