Carcinogenicity of diethylnitrosamine in vitamin-A-deficient mice.
The effect of suboptimal levels of dietary vitamin A on diethylnitrosamine (DEN) carcinogenesis was studied in BALB/c and Swiss mice. Two different dietary regimens were employed to induce vitamin A deficiency and DEN was administered by gavage at 2 dose levels: 0.6 mg/kg as a single dose and 200 mg/kg in 4 divided doses. Shark liver oil (SLO) which was the main source of vitamin A in the standard diet, was deleted in one regimen and reduced to 25% in the other. The mice maintained on the former diet were given a high dose of DEN and those on the latter diet received a low dose. In both strains the deficient mice had a greater tumour incidence than those on standard diet with a marginal reduction in the latent period. At the low level of DEN there was shift in organotrophy, i.e. from liver in controls to lung in the vitamin-A-deficient mice of BALB/c strain. With the higher dose, lung adenomas predominated in deficient as well as control groups in both the strains. Forestomach carcinomas appeared in deficient mice and not in the controls.
Carcinogenesis Division, Cancer Research Institute, Tata Memorial Centre, Bombay, India.
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Santhanam
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Lalitha
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D000284:Administration, Oral; D000818:Animals; D004052:Diethylnitrosamine / Q000633:toxicity*; D004198:Disease Susceptibility; D005260:Female; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009374:Neoplasms, Experimental / Q000139:chemically induced* / Q000209:etiology; D014801:Vitamin A / Q000008:administration & dosage; D014802:Vitamin A Deficiency / Q000150:complications*
D014801:Vitamin A; D004052:Diethylnitrosamine