We devised a clinical test of renal metabolism based on the synthesis of guanidinoacetic acid from citrulline in the proximal convoluted tubule. Intravenous administration of a citrulline/creatine solution to rats with modified levels of renal glycine amidinotransferase activity revealed a strong correlation (r = 0.921) between this activity and urinary ...

We have sought to define urinary acid-base excretion in the marine teleost using the long-horned sculpin, Myoxocephalus octodecimspinosus. Urine flow (1.7 ml.h-1.kg-1) is relatively high, and glomerular filtration rate is very low (2.9 ml.h-1.kg-1). The urine-to-plasma ratio of inulin is 2. Renal clearance of p-aminohippurate is very high (108 ml.h-1.kg-1); ...

A primary route of inactivation of leukotrienes and their receptor antagonists (LTRA) is metabolism by omega oxidation. SK&F 102922 [5-(2-(8-phenyloctyl)phenyl)-4,6-dithianonanedioic acid] is a LTRA that was designed to be resistant to omega oxidation. Therefore, these experiments were designed to characterize the metabolic fate of [14C]SK&F 102922. Following iv administration of ...

We have compared a new isolation procedure for urinary organic acids using strong anion-exchange columns with a solvent partition (ethyl acetate) method. Urinary samples from two healthy children and from nine children with organic acidurias were analysed by both procedures. Although the solid-phase extraction is more efficient for polyhydroxy acids, ...

To study mechanisms involved in renal glutamate dehydrogenase (GDH) regulation in response to systemic acid loading, we have measured blood pH, ammonium excretion, renal GDH mRNA levels, and GDH activity in rats. Acid intake (0.28 M NH4Cl in drinking water for 3 days) increased GDH mRNA levels in the renal ...

1. The effect of sodium propionate on urinary excretion of orotic acid was investigated. 2. Solutions containing sodium propionate or NaCl, 750 mM/day each, were continuously infused into the rumen for 10 days. 3. During NaCl infusion, an urinary orotic acid excretion of 290 +/- 80 micrograms/day was noted. The ...

Urinary beta-aminoisobutyric acid (ABA) concentration was determined by fluorometric high performance liquid chromatography in 22 workers occupationally exposed to lead. The urinary excretion of ABA was increased with increasing exposure to lead. The excretion of urinary ABA had a significant correlation with concentration of lead in blood (Pb-B) (r = ...

The mechanism of kidney damage commonly seen in patients with intravascular hemolysis is not entirely clear. Injection of distilled water (4 ml within 5 seconds) into the carotid arteries of rats resulted in intravascular hemolysis leading to hemoglobinemia, hemoglobinuria, reduction in inulin clearance, and elevation of urine N-acetyl-beta-D-glucosaminidase (NAG) excretion. ...

The metabolism and pharmacokinetics of pivalic acid, a major metabolite of S-1108, were studied with three healthy volunteers. Concentrations of S-1006 (the active compound), pivalic acid, and pivaloylcarnitine in plasma and urine were measured after administration of S-1108. Recoveries in urine at the doses of S-1108 given (100 and 200 ...

A patient with 3-hydroxy-3-methylglutaric aciduria was diagnosed using gas chromatography mass spectrometry. The patient had severe metabolic acidosis, hypoglycemia and hyperammonemia and excreted abnormal amounts of 3-methylglutaconic, 3-hydroxy-3-methylglutaric, 3-methylglutaric, 3-hydroxyisovaleric and glutaric acids in the urine. 3-Hydroxy-3-methylglutaric acid appeared as two peaks on the chromatogram after trimethylsilylation. One was a ...

Incomplete renal tubular acidosis (RTA) and overt distal RTA may be different stages of the same underlying pathophysiology in certain individuals. The rationale that draws these conditions together is the relatively alkaline pH of the urine, hypocitraturia, and a possible familial association. The rate of excretion of ammonium (NH4+), on ...

The urinary excretion profiles of some metabolites of sulfur mustard were determined by gas chromatography/mass spectrometry after cutaneous application of sulfur mustard in rats. Excretion profiles of the individual metabolites thiodiglycol and thiodiglycol sulfoxide, derived from the hydrolysis of sulfur mustard, were determined in different groups of three rats. Concentrations ...

Acetaminophen (paracetamol) is extensively conjugated with glucuronic acid and sulfate prior to renal excretion. A minor metabolic route involves microsomal oxidation of acetaminophen to a hepatotoxic reactive intermediate, which subsequently undergoes glutathione (GSH) conjugation, yielding cysteine and mercapturate conjugates, both of which are excreted in the urine (Slattery et al., ...

Rats were exposed to toluene at a wide range of concentrations from 50 to 4000 ppm for six hours, and the effects of ethanol and phenobarbital (PB) treatments on the pharmacokinetics of toluene metabolism were investigated. Ethanol treatment influenced toluene metabolism mainly at low exposure concentrations. Thus ethanol accelerated the ...

Diethylenetriaminepentaacetic acid (DTPA), ethylenglycolbis-(beta-amino-ethylether)-N,N-tetraacetic acid (EGTA), tartaric acid, KRYPTOFIX 222, and KRYPTOFIX 5 were evaluated for their efficacy in mobilization of strontium from the body of mice which had received 20 sc injections of strontium nitrate (95 mg/kg/injection) for 4 w. Twenty-four hours after the last strontium injection, ip administration ...

To better define the relative role of metabolic factors in the recurrence of stone formation, we studied the 24-hour urinary excretion of calcium (uCa), citrate (uCit), oxalic acid (uOx) and uric acid (uUa) in 73 male patients with primary calcium oxalate urolithiasis. According to the episodes of stone formation per ...

Meso-2,3-dimercaptosuccinic acid (DMSA) is bound to plasma albumin in humans and appears to be excreted in the urine as the DMSA-cysteine mixed disulfide. The pharmacokinetics of DMSA have been determined after its administration to humans po. For the blood, the tmax and t1/2 were 3.0 h + 0.45 SE and ...

6-n-Alkylchromone-2-carboxylic acids are metabolized solely by aliphatic oxidation. In the rabbit, the 6-n-propyl congener (PCCA) undergoes omega-1 hydroxylation exclusively. Following administration of PCCA to female Dutch rabbits (500 mumol/kg), some 77% of the dose was excreted in the urine, 41% as PCCA and 36% as 6-(2'-hydroxy-n-propyl)chromone-2-carboxylic acid. Since this metabolite ...

The acute renal effects of hypoxemia-reoxygenation and the putative protective action of WR-2721 [S-, 2-(3-aminopropyl-amino)-, etylphosphosphorothioic acid], a drug with specific properties such as PTH-secretion inhibiting, calcium lowering and free radical scavenging activities, were investigated in anesthetized-ventilated rabbits. Glomerular filtration rate (GFR) and renal blood flow (RBF) were assessed by ...

Using capillary gas chromatography-mass spectrometry, the effects of birth asphyxia on the urinary organic acid profile of term babies was investigated. Random urine samples were collected on days 1 and 8 from 19 babies with fetal distress, 19 with moderate birth asphyxia and 12 with severe asphyxia causing encephalopathy. Controls ...

After oral administration of 5-aminosalicylic acid a substantial proportion of the acetylated form is excreted in the faeces. We have studied the role of the faecal microflora in acetylating 5-aminosalicylic acid. In faeces incubated under both aerobic and anaerobic conditions there was acetylation of 5-aminosalicylic acid. Of the anaerobic bacteria ...

Toxicants can be converted in vivo by a variety of biotransformation reactions into substances that are more, equally, or less noxious than the parent compound. Although conjugation with glutathione is a process that usually results in less harmful products, these products might subsequently form new metabolites that exert more toxicity ...

In normal subjects fed western-mixed diets, in the fasting state, 39.6% of the variance of calciuria is accounted for by net acid excretion and 4% by sulfaturia. In the postprandial period, net acid accounts for 6.9% and sulfaturia for 11.8% of the variance of calciuria. As expected, after a load ...

Increased renal ammoniagenesis is pathogenic in animals. Thus, tubular degradation of filtered proteins to ammonia might link proteinuria to disease progression. The tubular uptake, metabolism and fractional degradation of aprotinin 99mTc (Trasylol), were measured in 26 glomerulonephritic patients with normal renal function, 10 with proteinuria > 5 g/24 h. In ...

The urinary excretion patterns of the serotonin (5-hydroxytryptamine; 5-HT) metabolites 5-hydroxyindole-3-acetic acid (5-HIAA) and 5-hydroxytryptophol (5-HTOL) were examined after ingestion of bananas, a food rich in 5-HT. The bananas contained on an average 25 micrograms 5-HT/g pulp. Both urinary 5-HIAA and 5-HTOL increased markedly (15- to 30-fold) shortly after eating ...

Ethylbenzene is an important industrial solvent and a key substance in styrene production. Ethylbenzene metabolism leads to the formation of mandelic acid, which occurs in two enantiomeric forms, and phenylglyoxylic acid. To decide which enantiomer is preferably formed, 70 urine samples of exposed workers were taken at the end of ...

In previous studies it could be shown that after bilateral nephrectomy (NX) the excretory function of the liver is disturbed. To further clarify whether or not this "renohepatic syndrome" is caused by toxic effects of uremia or by competition phenomena between various uraemic toxins an additional aspect was investigated: the ...

Urinary amino acids were isolated from the urine of healthy controls and a patient with a short bowel syndrome. Following derivatization with isopropyl alcohol/HCl and trifluoroacetic anhydride the amino acid enantiomers were separated by gas chromatography on a Chirasil-L-Val column. All subjects excreted D-alanine (10-30% of total Ala). The percentage ...

The excretion of 2-(2'-octenyl)succinic acid (OSA) and several metabolites of OSA was studied by gas chromatography/mass spectrometry in 17 infants and children fed one of three proprietary elemental or protein-hydrolysate formulas that use OSA-modified cornstarch as an emulsifying agent. Variable but often large amounts (up to 2500 mg/g creatinine) of ...

Urinary excretion of beta-aminoisobutyric acid (ABA) and delta-aminolevulinic acid (ALA) was investigated in mice exposed to lead (500 p.p.m.) in drinking water for 14 days. Concentrations of both urinary ABA and urinary ALA increased significantly in the lead-exposed mice. However, the degree of increasing excretion was higher in urinary ALA ...

The sodium salt of 2,3-dimercaptopropane-1-sulfonic acid (DMPS) is used p.o. for the treatment of chronic lead and Hg intoxication in humans. The metabolism and pharmacokinetics of DMPS were determined after p.o. administration of 300 mg of DMPS to each of 10 normal young men. The absorbed DMPS was metabolized rapidly ...

The effect of increasing the time interval between strontium exposure and chelation therapy was studied in male Swiss mice. Diethylenetriaminepentaacetic acid (DTPA), ethyleneglycol-bis-(beta-amino-ethylether)-N,N'-tetraacetic acid (EGTA), 4,7,13,16,21,24-hexaoxa-1,10-diazabycyclo[8.8.8]-hexacosane (Kryptofix 222), tartaric acid, and 1,13-bis(8-chinolyl)-1,4,7,10,13-pentaoxatridecan (Kryptofix 5) were administered intraperitoneally at 0, 6, 12, and 24 h after subcutaneous injection of 1,139 mg/kg ...

In our previous studies we were able to show that L-citrulline is taken up across the contraluminal membrane into the tubule cells of the isolated perfused non-filtering kidney of the African clawed toad (Xenopus laevis). We have also described the tubular metabolism of the L-citrulline taken up. The remaining question ...

Metabolites of CBD excreted into the bile and perfusion fluid were examined in a rat liver perfusion preparation. Metabolites were extracted with ethyl acetate and identified by GC/MS as TMS derivatives. Four mono- and five di-hydroxy metabolites were identified with major sites of metabolic attack being at C-7 and C-4". ...

Metabolism of methanol, methyl ethers, esters and amides give rise to formic acid. This acid is an inhibitor of the mitochondrial cytochrome oxidase causing histotoxic hypoxia. Formic acid is a weaker inhibitor than cyanide and hydrosulphide anions. The body burden of formate in methanol poisoning is high enough to cause ...

A 74-year-old female was diagnosed as having xanthinuria by measurement of the uric acid level in plasma, purine bases in urine and activity of xanthine oxidase in the duodenal mucosa. The determination of the urinary excretion of purine bases in her family demonstrated a slightly increased urinary excretion of oxypurines ...

Electrokinetic studies namely hydrodynamic permeability, electroosmotic permeability and streaming potential measurements of aqueous solutions of oxalic acid and urea have been made across urinary bladder membranes of goat. Energy conversion maxima and degree of coupling for these permeants have computed. It has been found that these values increase with increases ...

Two chemical substances isolated from adult flies of Drosophila melanogaster differently affected the emigration activity of genetically different strains. These substances were identified as palmitic acid and oleic acid, respectively. Chemical and biological comparisons of the natural and authentic compounds showed them to be identical. The behavior response was dependent ...

Renal hydrogen ion excretion increases with chronic acid loads and decreases with alkali loads. We examined the mechanism of adaptation by analyzing vacuolar proton-translocating adenosine triphosphatase (H+ ATPase) 31-kD subunit protein and mRNA levels, and immunocytochemical distribution in kidneys from rats subjected to acid or alkali loads for 1, 3, ...

The excretion of thioethers in urine of applicators occupationally exposed to the soil fumigant 1,3-dichloropropene (DCP) was determined by the thioether assay. The mercapturic acid metabolite of E-1,3-dichloropropene, N-acetyl-S-(E-3-chloropropenyl-2-)-L-cysteine (E-DCP-MA), was the reference compound in the thioether assay. The mean recovery of E-DCP-MA was 58.5% (coefficient of variation (CV) 9%, ...

A 9-year-old girl presented with a red scaly rash confined to sun-exposed areas which started at 2 years of age and had the appearance of pellagra. Investigation of urinary tryptophan metabolites following an oral tryptophan load, showed increased excretion of kynurenine and kynurenic acid but reduced excretion of 3-hydroxy-kynurenine, xanthurenic ...

Azelaic acid was the first dicarboxylic acid proposed as an alternative energy substrate in total parenteral nutrition. In this study, the pharmacokinetics of azelaic acid were investigated in 12 healthy volunteers, 7 receiving a constant infusion (10g over 90 min) and 5 a bolus dose (1g). The 24h urinary excretion ...

Plasma and urinary concentrations of different amino acids were investigated during diabetic ketoacidosis (DKA) and 12, 24, 72 hours after initiation of therapy. In DKA, plasma concentration of glutamic acid, aspartic acid, valine, leucine and isoleucine significantly increased while that of asparagine and glutamine decreased compared to levels in well-controlled ...

The metabolic fates of 4-14C- and 21-3H-labelled corticosteroids have been investigated in the rabbit by analysis of the normalized isotope ratios of neutral and acidic metabolites excreted in the urine. Isotope ratios of excreted radioactivity declined in the order cortisol (F) greater than corticosterone (B) greater than 11-desoxycortisol (S) greater ...

Fasted Bolivian squirrel monkeys (BoSM) exhibit a marked hyperbilirubinemia when compared to fed BoSM. This fasting hyperbilirubinemia (FH) is similar to that in human patients with Gilbert's syndrome. Endogenous bilirubin (BR) excretion (production) into bile was elevated two-fold in BoSM upon fasting. The fraction of injected dose of 3 H-amino-levulinic ...

A new loop diuretic with uricosuric activity, 6,7-dichloro-5-(N,N-dimethylsulfamoyl)-2,3-dihydro-2-benzofuran carboxylic acid (S-8666), was given orally at 12:00 a.m. or 12:00 p.m. in rats. The diuretic of S-8666 and the urinary excretions of the drug and its active metabolite S-8680 (N-demethyl S-8666) were greater at 12:00 a.m. than at 12:00 p.m. Thus, ...

An embryotoxic oral dose of bis(2-methoxyethyl) ether (DGDME), 3.73 mmol/kg body wt (500 mg/kg), administered on the 11th day of gestation to pregnant CD-1 mice was metabolized predominantly by O-demethylation to 2-(2-methoxyethoxy)ethanol with subsequent oxidation to (2-methoxyethoxy)acetic acid. Urinary excretion of this metabolite over 48 hr amounted to 63 +/- ...

In a group of 5 patients it was found that the presence of succinylacetone in urine as well as increased urinary excretion of delta-aminolaevulinic acid are a good criterion for the diagnosis of type I tyrosinaemia, and may serve for monitoring of the effectiveness of treatment with low-tyrosine diet. Determination ...

There are currently no reliable early markers of renal tubular damage. Since aminoaciduria is an accompanying feature of this condition, the usefulness of increased urinary amino acid excretion as a marker was investigated by inducing renal tubular necrosis in male Wistar rats by the administration of gentamicin (40 mg/kg/d) for ...

The aim of this investigation was to compare two formulations of the prodrug olsalazine (OLZ) with regard to local bioavailability of 5-aminosalicylic acid (5-ASA) in the colon. Since 5-ASA can not be measured directly in the colon, the bioavailability was evaluated by studying the plasma concentration and cumulative urinary excretion ...