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Mixed-function oxidation in tumors.

H D Brown·S K Chattopadhyay·S N Pennington·J S Spratt·H P Morris
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Abstract

Liver microsomes of the rat contain a group of hydroxylating enzymes which are coupled to a greater or lesser degree to the electron flow system. In our studies, enzymes believed to be directly associated with the electron flow chain of NADPH, ferricyanide reduction, cytochrome c, cytochrome P-450 and substrate hydroxylation have been observed in livers obtained from normal, tumor-bearing and whole body irradiated rats as well as in Morris hepatoma 7777 and dimethyl-amino-biphenyl induced breast tumors.A significant difference appeared to exist in the activity of NADPH oxidase, NADP-ferricyanide reductase and benzopyrene hydroxylase when normal liver was compared with the liver obtained from a breast-tumor-bearing animal. Both cytochrome P-450 and cytochrome b(5) were decreased in the tumor-bearing animal.Tissue distribution of benzopyrene hydroxylase in normal, lactating and tumor-bearing Wistar rats has been studied.With the exception of NADPH oxidase, the activities of NADP-cytochrome c reductase, NADPH-ferricyanide reductase, benzopyrene hydroxylase and P-450 were markedly different in liver from Morris hepatoma 7777-bearing Buffalo rat when this was compared with homologous tissue obtained from normal Buffalo rat.Whole-body irradiated animals showed increased P-450 and NADPH oxidase activity in liver as a function of irradiation and there further appeared to be a correlation with decreased ferricyanide reductase activity.

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AnimalsBenzopyrenesBiphenyl CompoundsCarcinoma, HepatocellularColonCytochromesElectron TransportFemaleFerricyanidesKidneyLactationLiver NeoplasmsLungMaleMammary Neoplasms, ExperimentalMicrosomes, LiverMixed Function OxygenasesNADPNeoplasms, ExperimentalOxidoreductasesPregnancyRadiation EffectsRatsJournal Article

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H D Brown, S K Chattopadhyay, S N Pennington, J S Spratt, H P Morris. 1971. Mixed-function oxidation in tumors.. https://doi.org/10.1038/bjc.1971.19

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