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.
Department of Surgery II, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
T
T
Yamada
H
H
Kuwano
H
H
Matsuda
K
K
Sugimachi
N
N
Ishinishi
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