Effect of dietary vitamin A on forestomach tumorigenesis during the total and postinitiation stages in mice treated with high- or low-dose benzo(a)pyrene.
The effects of dietary vitamin A on forestomach tumorigenesis during the total stage of the initiation and postinitiation periods and during the postinitiation stage were evaluated in ICR/Jcl mice treated with either high or low doses of benzo(a)pyrene (B(a)P). In experiment 1, the animals were initiated with a high carcinogenic dose of B(a)P to a total of 20 mg, while in experiment 2 the animals were treated with a low dose of B(a)P to a total of 2 mg. A control group of animals received no carcinogens. Five different dietary levels of vitamin A supplements were used in each experiment and in the control study. In experiment 1, a high incidence of tumorigenesis was observed in every group, with 74% to 96% developing papilloma and 19% to 46% developing carcinoma. In experiment 2, the incidence of tumorigenesis in the high-dose vitamin A groups, including those given during the total and postinitiation stages, was found to be significantly reduced at 7.4%, compared with that in the low-dose vitamin A group of 57.7% (P < 0.05). These results suggest that a high dietary level of vitamin A can reduce the incidence of tumorigenesis when low carcinogenic dose levels of B(a)P are given in both the total and postinitiation stages.
Yamada
T
T
Department of Surgery II, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Kuwano
H
H
Matsuda
H
H
Sugimachi
K
K
Ishinishi
N
N
D000818:Animals; D001564:Benzo(a)pyrene / Q000008:administration & dosage*; D002273:Carcinogens / Q000008:administration & dosage*; D002294:Carcinoma, Squamous Cell / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control; D016009:Chi-Square Distribution; D005527:Food, Fortified; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D010212:Papilloma / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control; D013274:Stomach Neoplasms / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D014801:Vitamin A / Q000008:administration & dosage / Q000494:pharmacology*
D002273:Carcinogens; D014801:Vitamin A; D001564:Benzo(a)pyrene