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.
Santhanam
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U
Carcinogenesis Division, Cancer Research Institute, Tata Memorial Centre, Bombay, India.
Lalitha
V S
VS
Bhide
S V
SV
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