Metabolism comparative

Wasserman, R.H., Lengemarm, F.W. and Comar, C.L. 1958 Comparative metabolism of calcium and strontium in lactation. Journal of Dairy Science 41 812-821. 

Anderson PN, Eaton DE, Murphy SD. 1992. Comparative metabolism of methyl parathion in intact and subcellular fractions of isolated rat hepatocytes. Fundam Appl Toxicol 18 221-226. 

Yamamoto T, Egashira T, Yoshida T, et al. 1983. Comparative metabolism of fenitrothion and methylparathion in male rats. Acta Pharmacol Toxicol 53 96-102. 

Microsomes are widely used to study the metabolism of xenobiotics. Enzymes can be chararacterized on the basis of their requirement for cofactors (e.g., NADPH, UDPGA), and their response to inhibitors. Kinetic studies can be carried out, and kinetic constants determined. They are very useful in studies of comparative metabolism, where many species not available for in vivo experiment can be compared with widely investigated laboratory species such as rats, mice, feral pigeon, Japanese quail, and rainbow trout. 

Brealey, C.J. (1980). Comparative Metabolism of Pirimiphos-methyl in Rat and Japanese Quail. Ph.D. Thesis, University of Reading, UK. 

Muller WF, Coulston F, Korte F. 1982. Comparative metabolism of " C-trichloroethylene in chimpanzees, baboons, and rhesus monkeys. Chemosphere 11 215-218. 

The above example illustrates the inherent problems that can arise in the use of standardised protocols for assessing chemicals naturally occurring in the food chain. Had work on comparative metabolism and pharmacokinetics been undertaken before any animal bioassay work, it could have given more useful information. The extrapolation of effects obtained in high-dose animal studies to a large number of people exposed to a low dose is not the most effective use of resources. Nor are such experiments consistent with biological reality. There are few chemicals that would not cause illness or death if the daily intake was increased some 100-1000 fold as is the situation in many... 

Pillai BVS, Swamp (2002) Elucidation of the flavonoid catabolism pathway in Pseudomonas putida PML2 by comparative metabolic profiling. Appl Environ Microbiol 68 143-151. 

Plant metabolism studies will provide information on the absorption, translocation, dissipation and degradation of the agrochemical. This information defines the residual analytes of regulatory concern that could include either the parent compound or metabolites in the field crops. Plant metabolism studies should be conducted with at least three crop representatives of three different crop groups listed in Table 1. One of the major objectives is to determine the comparative metabolism of the agrochemicals between animals and plants among different plant species. MAFF approves metabolism studies that are conducted in foreign countries, which should be operated under the certified GLP system. 

Weiss DJ, Geary RS, Wustenberg W, et al. 1994. Comparative metabolism of diisopropyl methylphosphonate in mink and rats. Arch Environ Contain Toxicol 27 420-425. 

Kaneko, H., H. Ohkawa, and J. Miyamoto. 1981. Comparative metabolism of fenvalerate and the [25,aS]-isomer in rats and mice. Jour. Pestic. Sci. 6 371-326. 

Mumtaz, M.M. and R.E. Menzer. 1986. Comparative metabolism and fate of fenvalerate in Japanese quail (Cotumix coturnix japonica) and rats (Rattus norvegicus). Jour. Agricul. Food Chem. 34 929-936. 

Sikka, H.C., J.P. Rutkowski, and C. Kandaswami. 1990. Comparative metabolism of benzo[a]pyrene by liver microsomes from brown bullhead and carp. Aquat. Toxicol. 16 101-112. 

Izumi T, Kaneko H, Matsuo M, Miyamoto J (1984) Comparative metabolism of the six stereoisomers of phenothrin in rats and mice. J Pestic Sci 9 259-267... 

No information is available as to whether metabolism of -hexane in children differs from that of adults. No studies were located comparing metabolism in young and adult animals. The toxicity of -hexane results from biotransformations yielding the active metabolite, 2,5-hexanedione. The initial step is an oxidation to 2-hexanol catalyzed by a cytochrome P-450 enzyme. Some P-450 enzymes are develop-mentally regulated (Leeder and Keams 1997). As the above discussion indicates, it is not completely clear which P-450 enzymes are involved in -hexane metabolism. 

Comparative Metabolism. Since the liver is the major organ involved in the biotransformation of xenobiotics, primary hepatocyte cultures provide an excellent model for in vitro metabolism studies. Primary hepatocyte cultures provide useful tools with which to study the comparative metabolism of xenobiotics by both humans and laboratory animals. 

Frakes RA, Sharma RP, Willhite CC, et al. 1986b. Comparative metabolism of linamarin and amygdalin in hamsters. Fd Chem Toxicol 24(5) 417-420. 

Although previous applications of this technique in our laboratory had been concerned with aquatic animal metabolism of pesticides such as DDT, parathion, carbaryl, and trifluralin (14, 15), we also became interested in comparing metabolic routesljy means of a "metabolic probe". Such a compound ideally should be stable to nonbiological degradation, of low toxicity to maximize the dose, and subject to as many major routes of metabolism as possible without undue analytical complexity. 

A comparable metabolic fate is documented for the hydraulic fluid tributyl phosphate. Following administration to rats, the Bu groups were oxidized to alcoholic, ketonic, and acidic metabolites. The oxidized Bu groups were then cleaved by enzymatic hydrolysis [103], With 2-ethylhexyl diphenyl phosphate (9.48), an interesting case of regioselectivity was noted during its in vivo metabolism in rats. Indeed, this flame retardant and plasticizer was... 

A comparable metabolic pattern was observed in the rat after oral administration of 3-([l,l -biphenyl]-4-yl)butanenitrile (11.84), a nonsteroidal anti-... 

Klos C, Dekant W. 1994. Comparative metabolism of the renal carcinogen 1,4,-dichlorobenzene in rat Identificaiton and quantitation of metabolites. Xenobiotica 24(10) 965-976. 

According to US-EPA (1993), its position, in general is that the potential for toxicity manifested via one route of exposure is relevant to considerations of any other route of exposure, unless convincing evidence exists to the contrary. Consideration is given to potential differences in absorption or metabolism resulting from different routes of exposure, and whenever appropriate data (e.g., comparative metabolism smdies) are available, the quantitative impacts of these differences on the risk assessment are delineated. 

Because the resistance of polyxenes to the toxic effects of linear furanocoumarins apparently does not extend to the angular furanocoumarins (22), we have undertaken comparative metabolic fate studies with a representative of each of these furanocoumarin classes. Tritlated psoralen or isopsoralen (Figure 1) was administered as before to last stage polyxenes caterpillars, and the distribution, elimination, and biochemical fate of the compounds determined (28). 

By analogy with malathlon, derivatives of this type were expected to be metabollcally degraded to nontoxic products In mammals by carboxylesterase action but to the parent methylcarbamate In Insects by phosphatase action (8). Thus, these derivatives were expected and found to be toxic to Insects and safe to mammals. Subsequent Investigations on the comparative metabolism of the N-dlmethoxyphosphlnothloyl derivative of carbofuran In Insects and rodents provided direct support for the rationale used In the design of these derivatives (9). 

The results of a comparative metabolism study of an aryl-sulfenyl derivative of carbofuran [2,2-dimethy1-2,3-dihydro-benzofuranyl-7 -methyl-N-(2-toluenesulfenyl)carbamate] in the house fly and white mouse Indicated the selective action of this compound to be a consequence of different metabolic pathways in insects and mammals (12). The arylsulfenyl group on the carbamate moiety allows the mammal to carry out metabolic reactions leading to less toxic products which are rapidly conjugated, while the toxic parent methylcarbamate is formed in the insect. 

Comparative Metabolism of Dithiolane Insecticides in Plants, Animals, and the Environment... 

Parker, R.J. et al. (2005) Stability and comparative metabolism of selected felbamate metabolites and postulated fluorofelbamate metabolites by post-mitochondrial suspensions. Chemical Research in Toxicology, 18 (12), 1842-1848. 

Comparative metabolism of the tobacco-specific nitrosamines 4-(meth-ylnitrosamino)-1 -(3-pyridyl)-1 -butanone and 4- (methylnitrosam ino) -1 - (3 -pyri-dyl)-l -butanol by rat cytochrome P450 2A3 and human cytochrome P450 2A13. Drug Metab Dispos 2003 31(10) 1199-1202. 

Ranny R.E. (1977). Comparative metabolism of ethinylestradiol in man. Journal of Toxicology and Environmental Health 3 139-166. 

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