A comparison of beta-carotene and vitamin A effects on a hepatocarcinogenesis model
1995
Moreno, F.S. | Wu, T.S. | Penteado, M.V.C. | Rizzi, M.B.S.L. | Jordao, A.A. Jr | Almeida-Muradian, L.B. | Dagli, M.L.Z.
The effects of beta-carotene (betaC) or vitamin A (VA) administration for 8 consecutive weeks were compared in male Wistar rats submitted to the resistant hepatocyte model (RH model) of hepatocarcinogenesis. Animals treated with corn oil (CO), instead of carotenoid or retinoid, served as controls. At the end of the study, betaC treatment resulted in a substantial reduction in the hepatocyte nodule incidence, total number of nodules and in the nodule multiplicity, as well as in the number and size of hepatic gamma-glutamyltranspeptidase (gammaGT)-positive foci. In contrast, animals administered with VA presented a 100% nodule incidence, and only a moderate decrease in the total number of hepatocyte nodules. These showed to be in the great majority larger than nodules observed after betaC treatment. Moreover, VA administration resulted in similar number and size of gammaGT-positive foci than controls. In addition, the hepatic concentrations of total VA increased in both, betaC and VA treated animals. However, as expected, increases in the hepatic carotenoid concentrations could be only observed after betaC application. Therefore, changes in the hepatic levels of betaC, and not of VA, resulted in appreciable inhibitory effects on preneoplastic lesions of the liver. The evidence implies that the chemopreventive property of betaC is unrelated to its provitamin A activity.
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