Taurine conjugation of arylacetic acids in the ferret

In vitro activation of the promutagens 2-acetamidofluorene, cyclophosphamide and 7,12-dimethylbenzanthracene by constitutive ferret and rat hepatic S-9 fractions

The ability of the ferret to metabolically activate promutagenic compounds was compared with that of the rat, using the Salmonella/microsome assay. Three compounds which require biotransformation to mutagenic metabolites, 2-acetamidofluorene (2-AAF), cyclophosphamide (CPA), and 7,12-dimethylbenzanthracene (DMBA), were studied. Metabolic activation was provided by ferret or rat hepatic S-9 fractions at 5 levels for each chemical, and optimal S-9 levels as well as dose-response curves were obtained. Interspecies mutagenic activity was quantitated on the basis of mg liver, mg S-9 protein, and nmoles P-450. The slopes of the dose-response curves and the lowest chemical dose required for a significant response were also compared. Although constitutive levels of rat hepatic cytochrome P-450 were shown to be higher than those of the ferret, in vitro mutagenic activation by ferret S-9, at S-9 levels which caused activation in both species, was greater than or equivalent to activation by rat S-9 for these chemicals, based on all parameters studied. The results showed that the equilibrium between activation and detoxification reactions is dependent upon the chemical dose and S-9 level present.

Influence of the gut microflora on the metabolism of 4-nitrobenzoic acid in the marmoset

1. 4-Nitrobenzoic acid was metabolized by the marmoset to amino derivatives to the extent of 18.8% (p.o.) and 11.4% (i.p.) of the dose. 2 Reduction of 4-nitrobenzoic acid was significantly decreased by antibiotic pretreatment; the mean decrease in reduction was 81% for animals doses orally and 73% for intraperitoneally dosed marmosets. 3. 4-Nitrohippuric acid was the major metabolite of 4-nitrobenzoic acid, accounting for 30.6% and 49.6% of p.o. and i.p. doses respectively. 4. Antibiotic pretreatment affected the marmosets' normal capacity to reduce 4-nitrobenzoic acid for many weeks after the initial administration. 5. Maximum radioactivity in the blood, after an oral dose, was reached in 30-40 min; the average half-life for the elimination of 4-nitro[carboxy-14C]benzoic acid and its metabolites was 30.4 +/- 3 min after an intramuscular dose. 6. Radioactivity of 4-nitro[carboxy-14C]benzoic acid representing 3.4% of the dose was excreted in rat bile in 24 h.

The ferret, Mustela putorius furo, as a new species in toxicology

Comprehensive studies on the haematology, urine chemistry, serum chemistry and gross pathology have been carried out and reported. Seasonal weight changes were confirmed and were initiated, together with sexual activity, when ferrets were brought in to a constant temperature (18-19 degrees C) and 14-hour daylight cycle during the winter months. Levels of haemoglobin, erythrocytes and haematocrit were higher than in most common laboratory species. Similarly, serum electrolytes and glucose levels were higher than in Wistar rats or beagle dogs. Ovaries, uteri and testes displayed a seasonal maturation and atrophy. All other parameters were similar to common laboratory species.

Taurine conjugation in metabolism of 3-phenoxybenzoic acid and the pyrethroid insecticide cypermethrin in mouse

1. A substantial proportion of the radioactivity of an oral dose (1-20 mg/kg) of 3-phenoxy [14C] benzoic acid and the pyrethroid insecticide trans- and cis-[aryl-14C] cypermethrin (an alpha-cyano-3-phenoxybenzyl ester) is eliminated rapidly in urine of mice. 2. The major urinary metabolite of these compounds in two strains of mice is N-(3-phenoxybenzoyl)taurine. 3. Neither 3-phenoxybenzoic acid nor cypermethrin gives a taurine conjugate in rats. 4. Benzoic acid gives no taurine conjugate in mice.

Taurine conjugates as metabolites of arylacetic acids in the ferret

1. The pattern of conjugation in the ferret of 8 arylacetic acids and, for comparison, benzoic acid and 4-nitrobenzoic acid was examined. 2. The arylacetic acids, phenylacetic, 4-chloro- and 4-nitro phenylacetic, alpha-methylphenylacetic (hydratropic), 1- and 2-naphthylacetic and indol-3-ylacetic acids, were excreted in the urine as taurine and glycine conjugates. Diphenylacetic acid did not form an amino acid conjugate and was excreted as a glucuronide. 3. The taurine conjugate was the major metabolite of 4-nitrophenylacetic, alpha-methylphenylacetic, 1- and 2-naphthylacetic and indol-3-ylacetic acids, whereas the glycine conjugate was the major metabolite of phenylacetic and 4-chlorophenylacetic acids. Taurine conjugation did not occur with benzoic and 4-nitrobenzoic acids which were excreted as glycine and glucuronic acid conjugates. 4. Phenacetylglutamine and 4-hydroxyphenylacetic acid were minor urinary metabolites of phenylacetic in the ferret. 5. A number of taurine conjugates of aliphatic and aromatic acids were synthesized and their characterization and properties were studied. The role of taurine as an alternative to glycine in the metabolic conjugation of arylacetic acids is discussed.

A comparison of the composition and apolipoprotein content of the lipoproteins isolated from human and ferret (Mustela putorius furo L.) serum

1. The lipoproteins isolated at densities of less than 1.006, 1.006-1.063 and 1.063-1.21 g/ml from human and ferret (Mustela putorius furo L.) serum were compared. 2. Ferret very low density lipoprotein contained proportionately less triglyceride and more phospholipid than human. 3. Ferret low density lipoprotein contained proportionately more triglyceride and less cholesterol than human. 4. High density lipoprotein was the major lipoprotein in ferret serum. 5. The gel electrophoretic patterns of lipoprotein apoproteins and the pattern of apoprotein solubility in tetramethylurea were similar for human and ferret fractions. 6. The ferret may provide a convenient animal for the study of serum lipoprotein structure, function and metabolism.

Metabolism of arylacetic acids. 1. The fate of 1-naphthylacetic acid and its variation with species and dose

1. [Carboxy-14C]-1-Naphthylacetic acid has been administered to man, 6 primate species and 4 other mammalian species and the urinary metabolites examined by radiochromatogram scanning and reverse isotope dilution. Animals all received a dose of 100 mg/kg and man received 5 mg, orally. 2. Most species excreted at least 60% of the 14C in the urine in 48 h. Unchanged acid was a minor (0-17% dose) excretion product in all species except the cynomolgus monkey (35%). 3. In man, in 24 h 95% of 14C was excreted as 1-naphthylacetyl-glucuronide and 5% as 1-naphthylacetyltaurine. 4. 1-Naphthylacetylglucuronide was the major excretion product in all species except the bushbaby (21% dose) and the cat, which did not form this conjugate. 5. 1-Naphthylacetylglutamine was formed only by the cynomolgus, squirrel and capuchin monkeys and marmoset, and in no case accounted for more than 3% dose. 6. 1-Naphthylacetylglycine was found in the urines of 4 primate and 3 non-primate species, and was the major metabolite in the squirrel monkey, bushbaby and cat. 7. 1-Naphthylacetyltaurine was excreted by all species except the rabbit and the fruit bat. It was a major excretion product in the squirrel and capuchin monkeys, the marmoset and the cat. 8. The influence of dose on the pattern of metabolism and excretion of 1-naphthylacetic acid has been investigated in the rat.