Enzymes hepatocarcinogenesis

PPAR Xenochemical Induction of CYP4A Enzymes and Role in Rodent Hepatocarcinogenesis... 

Puatanachokchai, R., Morimura, K., Wanibuchi, H., Oka, M., Kinoshita, A., Mitsuru, E., Yamaguchi, S., Eunae, Y., and Eukushima, S. (2006). Alpha-benzene hexachloride exerts hormesis in preneoplastic lesion formation of rat hepatocarcinogenesis with the possible role of hepatic detoxifying enzymes. Cancer Lett 102-113. 

Satoh, K., Kitahara, A., Soma, Y., Inaba, Y., Hatayama, I., and Sato, K., Purification and distribution of placental glutathione transferase A new marker enzyme for preneoplastic cells in the rat chemical hepatocarcinogenesis. Proc. Natl. Acad. Sci. U.SA. 82, 3964-3968 (1985). 

In the rodent, the evidence for liver tumors in response to PPs is clear and unequivocal. In addition to this hepatocarcinogenesis, PPs induce peroxisome proliferation associated with the increased expression of enzymes found in the peroxisome that are responsible for metabolism of fatty acids. One of the key enzymes in this pathway is acyl CoA oxidase, ACO. Levels of ACO are increased dramatically in the livers of rodents treated with PPs but there is no increase in this enzyme in humans. Because of the close association between peroxisome proliferation and ACO, this enzyme is used as a marker or indicator of the rodent response to PPs. The hnk between peroxisome proliferation and hepatocarcinogenesis remains to be elucidated. However, evidence suggests a commonality and there is consensus that peroxisome proliferation is necessary but not srrfficient per... 

In sununary, these studies do not offer evidence that ethanol effects on MFO enzyme activities, even if significant, are sufficient to reliably account for any effects on hepatocarcinogenesis. However, it is possible that other ethanol-feeding protocols, perhaps in other species and over a longer time, may yield more positive information. 

Scherer, E., and Emmelot, P., 1976, Kinetics of induction and growth of enzyme-deHcient islands involved in hepatocarcinogenesis. Cancer Res. 36 2544. 

Sarkar A, Mukheijee B, Chatlerjee M (1995) Inhibition of 3 -methyl-4-dimethylaminoa-zobenzene-induced hepatocarcinogenesis in rat by dietary P-carotene changes in hepatic anti-oxidant defense enzyme levels. Int J Cancer 61(6) 799-805... 

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