Hepatic mixed-function oxidase activity

Gerhart, E.H. and R.M. Carlson. 1978. Hepatic mixed-function oxidase activity in rainbow trout exposed to several polycyclic aromatic compounds. Environ. Res. 17 284-295. 

Robertson P, White EL, Bus JS. 1989. Effects of methyl ethyl ketone pretreatment on hepatic mixed-function oxidase activity and on in vivo metabolism of -hexane. Xenobiotica 19(7) 721-729. 

Hepatic mixed-function oxidase activities demonstrated seasonal trends, with higher specific activities in the cold weather months in both populations with few differences in enzyme activities or cytochrome levels between the two populations. Metabolism of aldrin, dieldrin and DDT was similar between the two populations. R fish have larger relative liver size and, therefore, a greater potential for xenobiotic metabolism. However, biotransformation appears to be of minor importance in chlorinated alicyclic insecticide resistance in mosquitofish barriers to penetration appear to be of greater importance and an implied target site insensitivity appears to be the most important factor in resistance. 

Figure 5. Dietary protein and hepatic mixed function oxidase activity (cytochrome c-reductase, cytochrome P-450, aryl hydrocarbon hydroxylase). (Reproduced with permission from Ref. 71. Copyright 1983, American Dairy Science Association.)...

El-hawari, A.M. and G.L. Plaa (1979). Impairment of hepatic mixed-function oxidase activity by alpha- and beta-naphthylisothiocyanate Relationship to hepato-toxicity. Toxicol. Appl. Pharmacol. 48, 445 58. 

Husain, M.M., Kumar, A. Mukhtar, H. (1984). Hepatic mixed-function oxidase activities of wild pigeons. Xenobiotica, 14, 761-6. 

Peterson, F. J., Holloway, D. E., Duquette, P. H., and Rivers, J. M., 1983, Dietary ascorbic acid and hepatic mixed function oxidase activity in the guinea pig, Biochem. Pharmacol. 32 91-96. 

Acute parenteral administration of cadmium decreases hepatic microsomal cytochrome P-450 content and inhibits associated mixed-function oxidase enzyme activities (Hadley et al. 1974 Means et al. 1979 Gregus et al. 1982). Decreases in hepatic mixed function oxidase activities and cytochrome P-450 content have been demonstrated after chronic cadmium dosing for 6 months (Dudley et al. 1985). The reduction in cytochrome P-450 is due to increased heme degradation, which results from cadmium stimulation of heme oxygenase activity (Maines and Kappus 1977 Eaton et al. 1980). Such an effect would alter the capacity of an organism to adequately biotransform endogenous compounds as well as other xeno-biotics. In mitochondria, cadmium inhibits the transmembrane transport of calcium (Webb 1979) and oxidative phosphorylation (Sporn et al. 1969). 

Woods JS, Carver GT, Fowler BA (1979) Altered regulation of hepatic heme metabolism by indium chloride. Toxicol Appl Pharmacol 49 455-461 Woods JS, Fowler BA, Eaton DL (1984) Studies on the mechanisms of thallium mediated inhibition of hepatic mixed-function oxidase activity correlation with inhibition of NADPH-cytochrome c (P-450) reductase. Biochem Pharmacol 33 571-576... 

A. L. Hunter and R. A. Neal, Inhibition of hepatic mixed-function oxidase activity in vitro and in vivo by various thiono-sulfur-containing compounds, Biochem. Pharmacol. 24, 2199-2205 (1975). 

NS (acute) (general population) Hepatic Decreased mixed function oxidase activity NS (children) Alvares et al. 1975 Saenger et al. 1984... 

L The answer is d. (Hardman, p 906.) Cimetidine slows the metabolism of Ca channel blockers, which are substrates for hepatic mixed-function oxidases. Inhibition of cytochrome P450 activity is peculiar to cimetidine and is not a mechanism of action of other histamine 2 (Hz) blockers. 

Knights KM, Gourlay GK, Cousins MJ. Changes in rat hepatic microsomal mixed function oxidase activity following exposure to halothane under various oxygen concentrations. Biochem Pharmacol 1987 36(6) 897-906. 

Mehendale HM, Chen PF, Fishbein L, et al. 1973. Effect of mirex on the activities of various rat hepatic mixed-function oxidases. Arch Environ Contam Toxicol 1(3) 245-254. 

Peppriell J. 1981. The induction of hepatic microsomal mixed-function oxidase activities in the mouse by mirex, 3,4,5,3 ,4 ,5 -hexachlorobiphenyl, and equimolar dosages of both. Environ Res 26 402-408. 

Hepatic microsomal mixed-function oxidase activity of several marine species from coastal Maine. Drug Metab. Dispos. 

Pohl, R. J., Bend, J. R., Guarino, A. M., and Fouts, J. R. Hepatic microsomal mixed-function oxidase activity of several marine species from coastal Maine. Drug Metab. Dispos. (1974) 2 545-555. 

Many other cases of carbon tetrachloride-induced hepatic and/or renal injury associated with ethanol ingestion have been described in the medical literature (Durden and Chipman 1967 Guild et al. 1958 Jennings 1955 Lamson et al. 1928 Markham 1967 Tracey and Sherlock 1968). These clinical reports establish that occasional or frequent ingestion of alcoholic beverages can increase the danger from relatively moderate carbon tetrachloride exposure. As ethanol is known to induce microsomal mixed-function oxidase activity in man (Rubin and Lieber 1968), the mechanism of potentiation may involve ethanol-induced enhancement of the metabolic activation of carbon tetrachloride. 

Gagne, F. and Blaise, C. (1993) Hepatic metallothionein level and mixed function oxidase activity in fingerling rainbow trout (Oncorhynchus mykiss) after acute exposure to pulp and paper mill effluents, Water Research 27 (11), 1669-1682. 

Fabacher, D. L., Kulkami, A. P. and Hodgson, E. (1980). Pesticides as inducers of hepatic drug-metabolizing enzymes—I. Mixed function oxidase activity. Gen. Pharmac. JJ, 429-435. 

Studies of the effects of typical inducers of mixed-function oxidase activity on DMN demethylation have also produced contradictory results. One group found that 3-methylcholanthrene and other PAH inhibited rat hepatic DMN demethylase activity (and DMN carcinogenicity) (474, 476), while others observed an increase in activity (136, 331, 374). Similar results were obtained in studies with Aroclor 1254, which was shown by one group to induce DMN demethylase activity in mouse liver (90), while other investigators found no change in activity (14). Contradictory results were also observed with phenobarbital (10, 13, 331, 374). These contradictions appear to have been at least partially resolved by the discovery of two hepatic forms of DMN demethylase. These two forms of DMN demethylase appear to respond differently to pretreatment with typical enzyme inducers one form is induced and the other repressed (11). The two different forms catalyze DMN demethylation at low substrate concentrations (0-4 mM)... 

James MO, Khan MAQ, Bend JR (1979b) Hepatic microsomal mixed-function oxidase activities in several marine species common to coastal Florida. Comp Biochem Physiol 62C 155-164 James MO, Sherman B, Fisher SA, Bend JR (1982) Benzo(a)pyrene metabolism in reconstituted monooxygenase systems containing cytochrome P-450 from lobster Homarus americanus) hepatopancreas fractions and N ADPH-cytochrome P-450 reductase from pig liver. Bull Mt Desert Isl Biol Lab 22 37-39... 

Pipe RK, Moore MN (1986) An ultrastructural study on the effects of phenanthrene on lysosomal membranes and distribution of the lysosomal enzyme 8-glucuronidase in digestive cells of the periwinkle Littorina littorea. Aquat Toxicol 8 65-76 Plesha PD, Stein JE, Schiewe MH, McCain BB, Varanasi U (1988) Toxicity of marine sediments supplemented with mixtures of selected chlorinated and aromatic hydrocarbons to the infaunal amphipod Rhepoxynius abronius. Mar Env Res 25 85-97 Pohl RJ, Bend JR, Guarino AM, Fonts JR (1974) Hepatic microsomal mixed-function oxidase activity of several marine species from coastal Maine. Drug Metab Disp 2 545-555 Post S, Wells MR (1985) Metabolism of aldrin by the freshwater planarian Phagocata gracilis. Bull Environ Contam Toxicol 34 871-875... 

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