Urine Of Guinea Pigs Research Articles

Vitamin C aspirin interactions in laboratory animals.

Ascorbic acid concentration has been determined in samples of plasma, leucocytes, urine, faeces and adrenal glands of guinea-pigs after administration of (i) 10, 25 or 100 mg ascorbic acid, (ii) 10 mg ascorbic acid plus 10, 25 or 50 mg aspirin and (iii) 25 mg aspirin and 25, 50 or 100 mg ascorbic acid. When the dose of aspirin was 25 mg or more, the transport of ascorbic acid into leucocytes was inhibited, the plasma concentration of vitamin C was elevated significantly and the excretion of ascorbic acid in the urine was increased in direct proportion to the aspirin dose. Ascorbic acid concentration in the adrenal glands was not significantly elevated after 3 h. When a constant dose of 25 mg of aspirin was given along with increasing doses of ascorbic acid both plasma and leucocyte ascorbic acid levels were elevated but not significantly after 2, 3 and 24 h. Urine ascorbic acid levels did not show any changes with the same doses.

Studies on endogenous formation of N-nitroso compounds in the guinea pig supplemented with proline or thioproline and sodium nitrate

The endogenous formation of N-nitrosoproline (NPRO) and N-nitrosothioproline (NTPRO, N-nitrosothiazolidine-4-carboxylic acid) was studied by monitoring their excretion in the urine of guinea pigs given oral doses of 10 mg proline or thioproline after supplementation with 34 mg (0.4 mmol) sodium nitrate. In order to estimate the conversion of nitrate to nitrate, the animals were also supplemented with 3.5 mg (0.05 mmol) sodium nitrate instead of sodium nitrate. In animals fed commercial diets, the excretion of NPRO and NTPRO under supplementation with sodium nitrate was 2.0 μg and 28.7 μg/animal/day, respectively, whereas the excretion under supplementation with sodium nitrate was 0.7 μg and 13.3 μg/animal/day, respectively. The higher excretion of NTPRO than NPRO in each case shows that thioproline is more effective for nitrite trapping than proline. The animals supplemented with nitrate excreted more than twice the amounts of NPRO or NTPRO than those supplemented with nitrite. It is assumed, therefore, that more than 0.1 mmol nitrate is reduced to nitrite and takes part in the endogenous nitrosation of the guinea pig. When various concentrations of l-ascorbic acid (AsA), known to inhibit the formation of N-nitroso compounds, were also administered orally to animals immediately after supplementation with sodium nitrate, the NPRO excretion decreased with increasing AsA concentration. These data indicate that the guinea pig, which is unable to synthesize AsA as well as humans, may be an appropriate animal model for evaluation of the endogenous nitrosation ability of humans ingesting nitrate.

Analysis of lamotrigine and lamotrigine 2-N-glucuronide in guinea pig blood and urine by reserved-phase ion-pairing liquid chromatography

Lamotrigine is an investigational anticonsulvant drug undergoing clinical trials. A simultaneous assay was developed to quantitate lamotrigine and its major metabolite, lamotrigine 2-N-glucuronide, from guinea pig whole blood. The extraction procedure and reversed-phase high-performance liquid chromatographic (HPLC) assay employed sodium dodecylsulfate (SDS) as an ion-pairing reagent to selectively separate lamotrigine and lamotrigine 2-N-glucuronide from endogenous blood components, other anti-convulsant drugs, and their metabolites. The mobile phase was composed of acetonitrile—50 m M phosphoric acid (pH 2.2) containing 10 m M SDS (33:67, v/v), and components were detected at 277 nm. The total coefficients of variance (C.V.) for the blood assay were ≤ 9.4% for lamotrigine (0.25–20.0 μg/ml) and ≤ 13.4% for the glucuronide metabolite (0.25–10.0 μg/ml). Separate assays for lamotrigine and its glucuronide in urine were developed. In order to quantitate low levels of lamotrigine in guinea pig urine, lamotrigine was extracted with tert.-butyl methyl ether—ethyl acetate (1:1). The total C.V. for lamotrigine quantitation in urine was ≤ 7.5% (0.10–10.0 μg/ml). For the determination of lamotrigine 2-N-glucuronide, urine was diluted with an SDS—phosphoric acid buffer (1:4) and injected directly onto the HPLC system, total C.V. ≤ 4.2% (0.5–50 μg/ml).

Evidence for the in vivo formation of ascorbic acid 2- O- α-glucoside in guinea pigs and rats

In vivo formation of ascorbic acid 2- O- α-glucoside (AA-2G) in guinea pigs and rats given ascorbic acid (AA) orally in combination with maltose was examined. A metabolite of AA which has the same HPLC retention characteristics as authentic AA-2G was detected in the blood, urine and liver of guinea pigs 1–2 hr after their administration. The metabolite was isolated from the urine by Chromatographie procedures and identified as AA-2G by its UV spectrum, non-reducibility, susceptibility to α-glucosidase hydrolysis, HPLC profile and elementary analysis. The same glucoside was also synthesized by rats and found in the urine, although it could not be determined qualitatively in the blood. AA-2G-forming activities of tissue homogenates from both animals were apparently correlated with their α-glucosidase activities and, moreover, both activities were completely inhibited by a specific neutral α-glucosidase inhibitor. Thus, we conclude that AA-2G is a possible metabolite produced by enzymatic α-glucosidation after a combined administration of AA and maltose to guinea pigs and rats.

Metabolism of mephentermine in male guinea pigs and male mice

1. Urinary metabolites of mephentermine (MP), after i.p. administration of MP to male Hartley guinea pigs and mice, were identified by g.l.c.-electron impact (EI) mass spectrometry. Excretion of urinary radioactivity, and metabolites of 3H-MP, after i.p. administration, were determined by preparative t.l.c.-liquid scintillation counting. 2. About 27% of the radioactivity administered was excreted in the 24 h urine of guinea pigs, and 36% dose was excreted in 5 days. In mice, about 47% of the radioactivity was excreted in the 24 h urine, and 52% in 5 days. 3. Excretion rates of metabolites detected in the 24 h urine of guinea pigs were phentermine (Ph, 7.8%), a conjugate of N-hydroxyphentermine (N-hydroxy-Ph, 3.6%), p-hydroxyphentermine (p-hydroxy-Ph, 1.0%) and its conjugate (2.9%), and other metabolites (conjugates of MP and Ph, N-hydroxymephentermine (N-hydroxy-MP) and its conjugate, p-hydroxymephentermine (p-hydroxy-MP) and its conjugate, and N-hydroxy-Ph; less than 1.0%). The rates of excretion for mice were Ph (11.7%), conjugates of p-hydroxy-MP (3.1%), Ph (2.7%) and p-hydroxy-Ph (1.6%), and N-hydroxy-Ph (1.2%) and other metabolites (conjugates of MP and N-hydroxy-Ph, N-hydroxy-MP and its conjugate, p-hydroxy-Ph, and p-hydroxy-MP; less than 1.0%). 4. These results indicate that MP administered to mice is metabolized mainly to Ph and p-hydroxy-MP by N-demethylation and p-hydroxylation of the parent compound, and in guinea pigs the primary metabolic reaction of MP is N-demethylation producing Ph.(ABSTRACT TRUNCATED AT 250 WORDS)

Metabolismin vivoof the tropane alkaloid, scopolamine, in several mammalian species

1. In vivo metabolism of scopolamine was studied in rats, mice, guinea pigs and rabbits. The structures of eight urinary metabolites including unchanged drug were elucidated by mass and nuclear magnetic resonance spectrometry. Determination of these metabolites was achieved by a g.l.c. method using a semi-capillary column. 2. The major metabolites in rats were the three phenolic metabolites, p-hydroxy-, m-hydroxy- and p-hydroxy-m-methoxy-scopolamine. 3. Significant intra-species difference of the metabolism was observed in rabbits. Tropic acid was the major metabolite in two rabbits out of three, while the other rabbit excreted mainly unchanged scopolamine, accompanied by five metabolites. Tropic acid was also the major metabolite in guinea pigs, but was of minor importance in mice. 4. The dehydrated metabolites, aposcopolamine and aponorscopolamine, were abundantly excreted in guinea pigs, moderately in mice, and least in rabbits and rats. 5. Excretion of glucuronide conjugates of scopolamine and norscopolamine were high in mice compared with other species. On the other hand, phenolic metabolites in rat urine; and tropic acid in rabbit and guinea pig urine, were excreted as the free forms. 6. These results indicate that scopolamine metabolism is highly species-specific.

Thermospray high performance liquid chromatography/mass spectrometric identification of a bladder carcinogen metabolite isolated from guinea pig urine

An in vivo urinary metabolite of the bladder carcinogen 2-amino-4-(5-nitro-2-furyl) thiazole was isolated from guinea pig urine and was identified by direct analysis using thermospray mass spectrometry/high-performance liquid chromatography as 1-(2-amino-4-(5-nitro-2-furyl)-2-thiazolyl)-1-deoxy-beta-D-glucopyran uronic acid. The structure of this metabolite was also established by chemical synthesis. Both positive and negative ion thermospray mass spectrometry of the conjugate showed fragment ions resulting from cleavage across the pyran ring of the glucuronic acid comprising of aglycone moiety. These characteristic fragment ions may be diagnostic for identification of N-glucuronides from O-glucuronides.

Excretion of Phenazopyridine and its Metabolites in the Urine of Humans, Rats, Mice, and Guinea Pigs

The metabolism of the urinary tract analgesic phenazopyridine [2, 6-diamino-3-(phenylazo)pyridine; PAP] was studied in the urine of humans, rats, mice, and guinea pigs. Urinary excretion was rapid in human and guinea pig, but in the rat and mouse it was slower and there was significant fecal excretion. Metabolism of PAP was extensive in all four species, and there were marked quantitative differences in the routes of metabolism. The extent of azo bond cleavage was high in the mouse and guinea pig, moderate in the rat, and low in humans. Hydroxylation of both the phenyl and pyridyl rings of PAP was observed in all species. In the human, 5-hydroxyl PAP was the major metabolite (48.3% of the dose). It was concluded that there are marked species differences in the metabolism of PAP, and that none of the species studied resembles the human; the rat comes closest, but cannot be considered a particularly good model.

Sandwich enzyme-immunoassay of human urinary trypsin inhibitor (urinastatin) and urinastatin-like immunoreactive substance in mouse urine

In the enzyme-immunoassay, using rabbit anti-urinastatin (anti-UT) Fab'-beta-D-galactosidase complex and rabbit anti-UT IgG-coupled polystyrene ball as a solid phase, the least measurable amount of UT was 0.3 ng per assay tube. The assay was used to detect UT-like immunoreactivity in the urine of mice. The urine contained a UT-like immunoreactive substance with trypsin inhibitory activity, the concentration of which was 2.3 +/- 0.3 micrograms/l (mean +/- SEM, n = 10). Excretion in the urine was affected by glucocorticoids. There was no immunoreactivity against rabbit anti-UT IgG in the urine of rats, guinea-pigs, rabbits, cats and dogs.

Species differences in metabolism of codeine: urinary excretion of codeine glucuronide, morphine-3-glucuronide and morphine-6-glucuronide in mice, rats, guinea pigs and rabbits

1. Metabolites of codeine were determined by use of h.p.l.c. in urine of male mice, rats, guinea pigs and rabbits injected with 10 mg codeine/kg subcutaneously. 2. In 24 h urines of these species, unchanged codeine, codeine glucuronide, free morphine, and morphine-3-glucuronide were as follows: mice, 6.8, 1.6, 0.8 and 7.6% dose; rats, 1.6, 0.2, 4.3 and 23.9% dose; guinea pigs, 1.6, 39.8, 0.2 and 1.6% dose; rabbits, 2.2, 24.5, 1.3 and 17.9% dose. Urinary excretion of morphine-6-glucuronide was 0.7% dose in guinea pigs, 1.9% in rabbits, and not detectable in mice and rats. Norcodeine was found only in the urine of mice. 3. These results indicate that codeine is metabolized in all four species by glucuronidation and by oxidative N- and O-demethylation, but the quantitative excretions of metabolites were quite different in different species.

実験動物アレルギーの臨床的，免疫学的研究 とくにモルモット上気道アレルギーを中心に

With the increasing numbers of individuals who take care animals, there has been a significant increase in the incidence of allergy to laboratory animals, and this has become an important social problem.The present study was carried out to clarify the mechanism of LAA, to identify the major allergens in guinea pig urine and saliva, and to find a way to prevent allergic symptoms.The patients were apt to have positive skin tests, high levels of serum specific IgE and immediate positive reactions to intranasal allergen challenge tests. LAA therefore seems to be a type 1 allergy. The molecular weights of major allergens determined by polyacrylamide gel electrophoresis and gel chromatography were 14, 000 to 18, 000 daltons in guinea pig urine and 15, 000 to 52, 000 daltons in guinea pig saliva. The results of RAST inhibition assays showed cross-allergenicity among guinea pig urine and saliva and serum and pelt and rat urine.A new type of air conditioning with better air flow (laminary air flow in one direction) than in the conventional turbulent flow system appeared to be effective for one of the ways to prevent LAA.

Influence of increased catecholamine levels in blood plasma during cold-adaptation and intramuscular infusion on thresholds of thermoregulatory reactions in guinea-pigs.

Catecholamines and some of their metabolites were determined in urine and blood plasma of guinea-pigs before, during and after acclimation to a cold or warm environment. During adaptation to 5 degrees C the amounts of noradrenaline in plasma and 24-h urine samples continuously increased up to 600% compared with values obtained at an ambient temperature of 22 degrees C. Higher levels of dihydroxyphenylglycol and 3-methoxy-4-hydroxyphenylglycol further indicated an increased turnover of noradrenaline during cold adaptation. Acclimation to an ambient temperature of 28 degrees C reduced the peripheral release of noradrenaline in comparison to the release observed at 22 degrees C. Cold-induced increases in metabolic rate and electrical muscle activity both occur at a considerably lower mean body temperature in cold-than in warm-adapted guinea-pigs. The shift of thermoregulatory cold defence reactions to a lower mean body temperature could also be observed in warm-adapted animals after intramuscular infusion of noradrenaline in amounts comparable to those released during cold adaptation. It is concluded that high peripheral sympathetic activity directly or indirectly inhibits noradrenergic neurons in the lower brain stem that modulate the thermoregulatory control system by means of their afferents to the hypothalamus. As a consequence of this peripheral influence the thermoregulatory set point is shifted to a lower mean body temperature.

Structural relationship between α1‐microglobulin from man, guinea‐pig, rat and rabbit

Rabbit alpha 1-microglobulin was purified from the urine of sodium-chromate-treated animals by the use of gel chromatography on Sephadex G-100, affinity chromatography on concanavalin-A--Sepharose and ion-exchange chromatography on DEAE-Sephadex. Rabbit alpha 1-microglobulin had a molecular mass of 25.6 kDa on SDS/polyacrylamide gel electrophoresis. Alpha 1-microglobulin has previously been purified from the urine of humans, guinea-pigs and rats by similar methods, and the molecular masses of the four homologues were compared by SDS/polyacrylamide gel electrophoresis and gel chromatography in a denaturing medium. By these two methods the human homologue was 6 kDa and 3 kDa larger, respectively, than the other three proteins. Endoglycosidase F digestion of alpha 1-microglobulin, followed by SDS/polyacrylamide gel electrophoresis, revealed three protein bands in the human alpha 1-microglobulin sample, and only two bands in guinea-pig, rat and rabbit alpha 1-microglobulin, with a gap between each band of 2.6--2.9 kDa. The amino-terminal amino acid sequences of the four homologues were determined and between 72% and 81% homology was seen. The five amino-terminal amino acids present in the other species were missing in guinea-pig alpha 1-microglobulin. Our results indicate that human alpha 1-microglobulin is substituted with two N-linked oligosaccharides, while only one is attached to each of the other alpha 1-microglobulins, and that the extra glycosylamine-linked oligosaccharide in the human protein is attached to asparagine in position 17. Finally it is shown that all four homologues inhibit antigen stimulation of human lymphocytes, a finding which is consistent with our previous suggestion that the N-linked oligosaccharides carry the immunosuppressive activity of alpha 1-microglobulin.

Analytical methods for the study of urinary thioether metabolites in the rat and guinea pig

Methods are described for the isolation and identification of three classes of bivalent sulfur metabolites characterized as neutral methylthio ethers, ethyl acetate-soluble acidic thioethers and ethyl acetate-insoluble acidic thioethers from rat and guinea pig urine. After extraction of the metabolites by the ammonium carbonate—ethyl acetate procedure, the individual metabolites are separated by capillary gas chromatography and/or by high-performance liquid chromatography with both μBondapak C 18 and Porasil columns. Identification of the metabolites is based on gas chromatography—mass spectrometry (electron impact) and on fast atom bombardment mass spectrometry. Interesting species differences in metabolism were observed. The major ethyl acetate-soluble acidic thioethers in rat urine are mercapturic acids. In contrast, in the guinea pig a new pathway involving mercaptopyruvic, mercaptolactic and mercaptoacetic acids is operative. The thioether metabolites of styrene oxide and phenanthrene are described, but the procedures have been applied in studies of several drugs and environmental chemicals in our laboratory.

Changes in peripheral metabolism of catecholamines in guinea-pig during thermal adaptation

1. 1.|Catecholamines and their final metabolites were determined quantitatively in urine of guinea-pigs ( Cavia aperea porcellus) during thermal adaptation by means of high performance liquid chromatography (HPLC) with electrochemical detection (ECD). 2. 2.|The daily release of free noradrenaline (NA) and 3-methoxy-4-hydroxyphenylglycole (MHPG) increased in cold adapted animals (5°C) up to 500% at the beginning of the third week of cold exposure (in comparison to animals kept at 22°C). Warm adapted animals (28°C) reduced NA and MHPG excretion by nearly 50%. 3. 3.|No significant changes in excreted amounts of adrenaline (A), dopamine (DA) and homovanillic acid (HVA) could be detected during thermal adaptation. 4. 4.|From these data it can be concluded that the exposure of warm adapted guinea-pigs to cold may lead to a 10 times higher peripheral release and turnover of NA.

Absorption, distribution, metabolism and excretion of a new morpholine derivative Y-8894 in mice, rats, guinea pigs and rabbits.

Absorption, distribution, metabolism and excretion of a new morpholine derivative Y-8894 were investigated in mice, rats, guinea pigs and rabbits by administration of 14C labeled compound (14C-Y-8894) at a dose of 30 mg/kg. Urinary and fecal recoveries of radioactivity (14C) within 4 days following oral administration were 52.2 % and 46.8 % in mice, 24.3 % and 72.5 % in rats, 73.4 % and 22.5 % in guinea pigs, and 64.8 % and 26.0 % in rabbits, respectively. About 93 % of the given 14C was recovered in the rat bile within 24 hours after oral administration. Maximum blood levels of 14C were obtained within 1 hour after oral administration in all species examined, with all initial biological half-lives (T 1/2) in the range of 1.0 ?? 1.8 hours. Terminal T1/2s were 21.2 ?? 25.8 hours for all species except the guinea pigs. The blood levels in guinea pigs were not detectable 24 hours after oral administration. The highest levels of 14C were observed in the liver, kidney and lung of mice, and in the liver of rats 0.5 hours after oral administration, and relatively high levels in the lung and kidney of rats, in the adrenal, pancreas, salivary gland and spleen of both mice and rats. Brain levels in both mice and rats were twice of that in the blood. Twenty-four hours after administration significant amount of 14C were detected only in the liver and kidney. Protein bindings of 14C in the serum were in the range of 63 ?? 83 % for all species. Major metabolites of Y-8894 in urine of mice were similar to those in urine and bile of rats, but somewhat different from those in urine of guinea pigs and rabbits.

Analytical methods for the study of urinary thioether metabolites in the rat and guinea pig

Methods are described for the isolation and identification of three classes of bivalent sulfur metabolites characterized as neutral methylthio ethers, ethyl acetate-soluble acidic thioethers and ethyl acetate-insoluble acidic thioethers from rat and guinea pig urine. After extraction of the metabolites by the ammonium carbonate—ethyl acetate procedure, the individual metabolites are separated by capillary gas chromatography and/or by high-performance liquid chromatography with both μBondapak C 18 and Porasil columns. Identification of the metabolites is based on gas chromatography—mass spectrometry (electron impact) and on fast atom bombardment mass spectrometry. Interesting species differences in metabolism were observed. The major ethyl acetate-soluble acidic thioethers in rat urine are mercapturic acids. In contrast, in the guinea pig a new pathway involving mercaptopyruvic, mercaptolactic and mercaptoacetic acids is operative. The thioether metabolites of styrene oxide and phenanthrene are described, but the procedures have been applied in studies of several drugs and environmental chemicals in our laboratory.

Method for determination of morphinone in urine and bile of guinea pig by high-performance liquid chromatography

Method for determination of morphinone in urine and bile of guinea pig by high-performance liquid chromatography

Catecholamines in the Vitreous Fluid and Urine of Guinea Pigs Dying of Cold and the Effect of Postmortem Freezing and Autolysis

Concentrations of catecholamines in vitreous fluid and urine in guinea pigs dying of cold and the effects of freezing and autolysis on these parameters were studied. The analysis was performed by high performance liquid chromatography with electrochemical detection. Noradrenaline (NA) concentration in vitreous fluid was more than 20 times higher in the cold exposed animals than in controls (44.2 +/- 9.2 versus 2.0 +/- 1.0 ng/mL). Autolysis alone caused an increase to 33.5 +/- 7.7 ng/mL, and freezing alone to 13.4 +/- 5.3 ng/mL. The highest values were in the group with exposure, freezing, and autolysis. Adrenaline (A) concentration in the vitreous fluid increased fourfold (3.9 +/- 1.5 versus 0.7 +/- 0.5 ng/mL) in cold exposure and twofold as a result of autolysis. Dopamine (DA) concentration in vitreous fluid was elevated only in the group with exposure, freezing, and autolysis. The increase of NA concentration in urine was fivefold during the whole exposure (from 19.4 +/- 6.9 to 109 +/- 57.3 ng/mL), but A was increased by twentyfold (from 10 +/- 5.1 to 213.2 +/- 168.7 ng/mL), whereas DA concentration did not change. The increase of average excretion of NA to urine was eightfold during the first 6 h of exposure, and that of A tenfold. According to the present results, elevated concentrations of catecholamines in the vitreous fluid and urine can be used as a diagnostic aid for hypothermia death. Concerning the values of noradrenaline in the vitreous, the increase as a result of autolysis must be taken in account when interpreting the results.

Biotransformation of diphenyl ether by trout and guinea-pigs after intraperitoneal administration.

Diphenyl ether (DPE) was administered intraperitoneally to rainbow trout (Salmo gairdneri) and guinea-pigs (Duncan Hartley). DPE metabolites in the urine and bile of trout and the urine of guinea-pigs were isolated and analysed by g.l.c.-mass spectrometry. No unchanged DPE was found in the biological fluids of guinea-pigs and trout. Only conjugated metabolites of DPE were present in the bile and urine of the trout: 4-hydroxy- and possible 3-hydroxy-DPE conjugates were found in the bile whereas 4-hydroxy- and 4,4-dihydroxy-DPE conjugates were detected in the urine. Both free and conjugated metabolites of DPE were isolated from the urine of guinea-pigs. These metabolites were 2-hydroxy-, 4-hydroxy, 4,4'-dihydroxy-, 4-methoxy-monohydroxy- and methoxy-dihydroxy-derivatives of DPE.