Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.31 (beta-glucuronidase)
 7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A radioimmunoassay for the measurement of both unconjugated and conjugaged estetrol in plasma has been developed. The antiserum obtained after 6 months of immunization with 6-oxoestetrol-6-(O-carboxy-methyl)oxim-BSA was used at a final dilution of 1:90,000 and showed almost no cross reaction with other steroids except for estriol at 1.24%. Esterol-glucosiduronate was synthesized by incubating with adrenalectomized rat liver homogenate and uridine diphosphoglucuronic acid. Then, plasma estetrol-glucosiduronate was measured in the same manner for unconjugated estetrol after hydrolysis with beta-glucuronidase. Sephadex LH-20 column chromatography (7X110 mm, benzene:methanol, 85:15) was employed for accurate assessment. The sensitivity was 10 pg and the smallest amount measurable was 40 pg/sample. The method bland was consistently negligible. The intra and inter assay precision was 11.8% and 14.2% for unconjugated estetrol and that for estetrol-glucosiduronate was 13.5% and 17.1%.
Steroids 1977 Oct
PMID:A radioimmunoassay of plasma unconjugated and conjugated estetrol. 20 82

Initial excretion studies with orally administered [monoethyl-1-3H] DES demonstrated the feces to be the principal mode of elimination of DES in the C3H mouse. Metabolic studies with tritiated DES and/or [UL-14C] DES were performed with orally dosed C3H high (MTV+) and low (MTV-) titer MMTV female mice. Extraction and partitioning of the fecal radioactivity demonstrated 77 to 86% (n = 4) to be benzene soluble and the remainder H2O soluble. The principal product in the organic phase following Sephadex LH-20 and HPLC purification was DES. The aqueous phase was resolved by LH-20 into two conjugate fractions that were partially hydrolyzed by beta-glucuronidase. The principal aglycone was chromatographically identical with authentic DES. The urinary conjugates were resolved into six fractions. The four major fractions were 80% hydrolyzable with beta-glucuronidase. Two of these fractions had trans-DES as the principal aglycone, whereas the other two had a major peak similar to but not chromatographically coincident with cis-DES. In certain experiments mice were sequentially dosed with tritium (24 hr) followed by a 14C dose (24 hr). Two mice (MTV+) were also previously fed 1000 ppb DES prior to these experiments. The tritated and 14C products were combined and analyzed simultaneously. This experiment did not reveal significant differences in the metabolism due to the modes of radioactive labeling, MMTV titer, or the prior feeding of DES. The developed methodology was judged to purify quantitatively 90% or more of the DES radioactive products.
Steroids 1978 Apr
PMID:Metabolism of diethylstilbestrol in the C3H mouse: chromatographic systems for the quantitative analysis of DES metabolic products. 66 80

The ability to form androgen conjugates and the hormone dependency of the conjugating enzymes have been studied in the rat epididymis. Following the in vitro incubation of 3H-testosterone with epididymal slices from intact and castrated rats, the radioactivity recovered was partitioned between water and ether. Examination of the water soluble radioactivity demonstrated the presence of glucuronides and sulfates. The total radioactivity in the conjugate fraction was the same for both intact and castrated animals. However, castrated rats showed a 3-fold increase in the glucuronide fraction with a corresponding decrease in the formation of sulfates. Characterization of the ether soluble radioactivity after solvolysis of the conjugate fraction from castrated animals, showed DHT (17beta-hydroxy-5alpha-androstan-3-one) and 3alpha-diol (5alpha-andro-stane-3alpha, 17beta-diol) to be the main metabolites. After beta-glucuronidase hydrolysis of the same, only 3alpha-diol could be demonstrated at a significant level, although traces of DHT and delta16 compounds were present. Corresponding hydrolysis of the water phase from incubation of epididymis from intact rats, demonstrated a marked quantitative difference. Here approximately 40% of the conjugated aglycones consisted of delta16 compounds, whilst only about 12% was comprised of 3alpha-diol. The preferential conjugation of DHT and 3alpha-diol to a sulfate radical was demonstrated in both intact and castrated rats. Since the conjugated delta16 compounds were detected only in the epididymis from intact animals, it is possible that these are formed by the spermatozoa.
Steroids 1976 May
PMID:Androgen metabolism by rat epididymis. 4. The formation of conjugates. 94 Nov 82

A simple, reliable and rapid radioimmunoassay (RIA) for the determination of testosterone glucosiduronate (TG) in crude urine is described. Two protein-TG complexes were investigated in raising antibodies: a) Bovine serum albumin (BSA)-TG and b) human plasma Cohn's fraction IV-4 (CF)-TG. In rabbits, high titers of antibodies were obtained after the injection of CF-TG. The specificity of the antiserum was sufficiently high (cross reaction with free testosterone 27%, with 5alpha-dihydrotestosterone-glucosiduronate 20%). TG was estimated in small aliquots of male and female urine after evaporation overnight at 50 degrees C in order to eliminate interfering material. The intraassay coefficient of variation (CV) was found to be 6% and the interassay CV 11%. TB has been determined in 40 samples of urine simultaneously by "direct" RIA and by a "classical" RIA following hydrolysis with beta-glucuronidase. The coefficient of correlation was found to be 0.89. The mean excretion of TG in the urine of 26 healthy men amounted to 164+/-51 mug/24 hours with a range from 97 to 346 mug/24 hours. In a group of 16 women a mean urinary excretion of TG of 24+/-10 mug/24 hours was determined. The method allows a technician to assay 40 samples per day.
Steroids 1976 Jul
PMID:A simple radioimmunoassay for the measurement of testosterone glucosiduronate in unextracted urine. 96 Jan 44

Four possible monoglucuronides of estetrol (estra-1,3,5(10)-triene-3,15 alpha, 16 alpha, 17 beta-tetraol) have been prepared from appropriately protected estetrol by the Koenigs-Knorr reaction employing cadmium carbonate as a catalyst. Condensation of methyl acetobromoglucuronate with estetrol 15,16,17-triacetate provided the 3-glucuronide acetate-methyl ester in a satisfactory yield. Introduction of the glucuronyl residue into C-17 was similarly attained by the use of estetrol 3-benzoate 15,16-acetonide. When estetrol 3,17-diacetate and acetobromosugar were stirred in anhydrous toluene in the presence of cadmium salt, the reaction occurred at C-16 and C-15 yielding two isomeric monoglucuronide derivatives in a ratio of ca. 5 to 2. Removal of the protecting groups in the four glucuronide acetate-methyl esters gave the desired estetrol glucuronides, respectively. These synthetic substrates underwent readily enzymatic hydrolysis with beef-liver beta-glucuronidase to afford estetrol.
Steroids 1976 Jan
PMID:Syntheses of estetrol monoglucuronides. 126 89

The hepatic metabolism of 3-oxoandrost-4-ene-17 beta-carboxylic acid (etienic acid), a probable acidic catabolite of deoxycorticosterone, was investigated using rats prepared with an external biliary fistula. Metabolic products were identified by GC-MS after hydrolysis with beta-glucuronidase and by proton nuclear magnetic resonance after chromatographic purification of protected glucuronides. About 80% of the injected dose was secreted into bile in 20 hours. Three fully reduced etianic acids (3 alpha-hydroxy-5 alpha-, 3 beta-hydroxy-5 alpha-, 3 alpha-hydroxy-5 beta-androstan-17 beta-carboxylic acids) were identified as were several of their di- and trihydroxylated congeners. Glucuronides of these reduced and/or hydroxylated metabolites constituted over half of the recovered dose, with carboxyl-linked glucuronides predominating over 3-hydroxyl-linked glucuronides. The mode of glucuronidation correlated well with the ability of liver microsomes to form the corresponding compounds in vitro from the set of four 3,5-diastereomeric etianic acids.
Steroids 1992 Jul
PMID:Hepatic metabolism of 3-oxoandrost-4-ene-17 beta-carboxylic acid in the adult rat: formation of carboxyl-linked glucuronides both in vivo and in vitro. 141 70

This paper describes the identification of a new bile alcohol possessing the 5 alpha-cholestane structure that was found in the urine of patients with cerebrotendinous xanthomatosis. The urine samples were extracted with reversed-phase resin, treated with beta-glucuronidase, and separated on silica gel and reversed-phase column chromatography. The new bile alcohol isolated was the second component of the urinary bile alcohols and was identified as (23S)-5 alpha-cholestane-3 alpha,7 alpha,12 alpha,23,25-pentol by means of gas-liquid chromatography/mass spectrometry and nuclear magnetic resonance spectroscopic studies.
Steroids 1991 Sep
PMID:Identification of (23S)-5 alpha-cholestane-3 alpha,7 alpha,12 alpha,23,25-pentol in urine of patients with cerebrotendinous xanthomatosis. 180 58

Bile alcohol glucuronides present in human serum were isolated by ion exchange chromatography on piperidino-hydroxypropyl Sephadex LH-20. Following hydrolysis with beta-glucuronidase, the bile alcohols were analyzed by a combination of gas-liquid chromatography and mass spectrometry. Bile alcohols identified were 27-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25-pentol, 27-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25,26-hexol, 5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25-pentol, 5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,26-pentol, 5 beta-cholestane-3 alpha,7 alpha,12 alpha,25,26-pentol, and 5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25,26-hexol. The bile alcohol composition in serum was similar to that in urine but not to that in bile. The concentration of total bile alcohols in serum was 59.5 +/- 24.6 micrograms/L.
Steroids
PMID:Identification of bile alcohols in serum from healthy humans. 324 75

Steroid acid esters, synthesized by modifying the 17-ketol side chain of prednisolone, were tested for their in vitro ability to stabilize heavy mitochondrial lysosomes prepared from rat liver. Membrane stabilization was determined by assessing capability of steroids to decrease extrusion of the marker enzymes (acid phosphatase, beta-glucuronidase and aryl sulfatase) from lysosomes incubated in hypo-osmotic sucrose-Tris acetate buffer. Results indicated that prednisolone (1) significantly inhibited the lysosomal release of acid phosphatase as did the new anti-inflammatory steroid, methyl 20-dihydroprednisolonate. Methyl prednisolonate exhibited weak membrane stabilization capacities and 20-dihydroprednisolonic acid, a metabolic product of methyl 20-dihydroprednisolonate, showed virtually no membrane stabilization.
Steroids 1981 Oct
PMID:Stabilization of rat liver lysosomes by new anti-inflammatory steroids in vitro. 689 65

Glycyrrhizic acid (GZA) and glycyrrhetinic acid (GRA) can be determined rapidly and precisely by high-performance liquid chromatography (HPLC) in biological fluids and tissues from experimental animals and humans. From plasma and tissues, GZA and GRA are extracted by organic solvents and the extracts can directly be used for HPLC. From bile or urine, extraction and determination of GZA and GRA are more difficult due to interfering endogenous compounds and conjugation of GRA with glucuronides or sulfates. Extraction of GZA and GRA from urine or bile can be performed by ion-pairing followed by extraction with organic solvents or by solid phase extraction. GRA conjugates can be determined by chromatographic separation or by pretreatment with beta-glucuronidase. The pharmacokinetics of GRA and GZA can be described by a biphasic elimination from the central compartment with a dose-dependent second elimination phase. Depending on the dose, the second elimination phase in humans has a half-life of 3.5 hours for GZA and between 10-30 hours for GRA. The major part of both GRA or GZA is eliminated by the bile. While GZA can be eliminated unmetabolized and undergoes enterohepatic cycling, GRA is conjugated to GRA glucuronide or sulfate prior to biliary excretion. Orally administered GZA is almost completely hydrolyzed by intestinal bacteria and reaches the systemic circulation as GRA.
Steroids 1994 Feb
PMID:Analysis and pharmacokinetics of glycyrrhizic acid and glycyrrhetinic acid in humans and experimental animals. 819 40


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