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PubMed1979

Strain differences in rat liver (UDP-glucuronyltransferase activity towards androsterone.

Male Donryu, Wistar King rats showed discontinuous variations in hepatic microsomal UDP-glucuronyltransferase activities towards androsterone, but not towards testosterone, bilirubin, phenolphthalein and 4-nitrophenol. Fresh microsomal fraction with a low transferase activity towards androsterone formed 0.049--0.080 nmole of glucuronide/min per mg of protein, whereas fresh microsomal fraction with a high transferase activity towards androsterone formed 0.335--0.557 nmol of glucuronide/min per mg of protein. The microsomal fraction with low enzyme activity towards androsterone was not stimulated by treatment with Triton X-100 or freezing and thawing. In contrast, male Long Evans and Sprague-Dawley rats did not exhibit such diversity.

Androsterone↗
PubMed2000

Purification and characterization of oxidoreductases-catalyzing carbonyl reduction of the tobacco-specific nitrosamine 4-methylnitrosamino-1-(3-pyridyl)-1-butanone (NNK) in human liver cytosol.

1. Four enzymes were purified to homogeneity from human liver cytosol and were demonstrated to be responsible for carbonyl reduction of the tobacco-specific nitrosamine 4-methylnitrosamino-1-(3-pyridyl)-1-butanone (NNK). 2. Carbonyl reductase (EC 1.1.1.184), a member of the short-chain dehydrogenase/reductase (SDR) superfamily, was compared with three isoenzymes of the aldo-keto reductase (AKR) superfamily in terms of enzyme kinetics, co-substrate dependence and inhibition pattern. 3. AKR1C1, 1C2 and 1C4, previously designated as dihydrodiol dehydrogenases (DD1, DD2 and DD4), showed lower K(m) (0.2, 0.3 and 0.8 mM respectively) than did carbonyl reductase (7 mM), whereas carbonyl reductase exhibited the highest enzyme efficiency (Vmax/K(m)) for NNK. Multiplication of enzyme efficiencies with the relative quantities of individual enzymes in cytosol resulted in a rough estimate of their contributions to total alcohol metabolite formation. These were approximately 60% for carbonyl reductase, 20% each for AKR1C1 and 1C2, and 1% for AKR1C4. 4. Except for AKR1C4, the enzymes had a strong preference for NADPH over NADH, and the highest activities were measured with an NADPH-regenerating system. Carbonyl reductase activity was extensively inhibited by menadione, rutin and quercitrin, whereas medroxyprogesterone acetate, phenolphthalein and flufenamic acid were potent inhibitors of AKR1C1, 1C2 and 1C4. 5. In conclusion, cytosolic members of the SDR and AKR superfamilies contribute to reductive NNK detoxification in human liver, the enzymes responsible being carbonyl reductase and aldoketo reductases of the AKRIC subfamily.

11-beta-Hydroxysteroid Dehydrogenase Type 1↗
PubMedDate not supplied

A cline in the acid phosphatase1 distribution in the Iberian Peninsula.

Blood samples from autochthonous and unrelated persons were examined for acid phosphatase (ACP1) phenotypes. The subjects were 143 Spanish Basques, 118 people from León and 295 from Castile. The samples were typed using starch gels, with one surface coloured with phenolphthalein diphosphate (Na5 salt) and the other surface revealed with 4-methylumbelliferyl-dihydrogenphosphate. The gene frequencies observed are compared with those obtained by other authors.

Acid Phosphatase↗
PubMed2001

Chromosome 11 allelotypes reflect a mechanism of chemical carcinogenesis in heterozygous p53-deficient mice.

Mice heterozygous for a null p53 allele were administered three well-characterized carcinogens to learn more about mechanisms of carcinogenesis and to evaluate the p53-deficient mouse as a tool for identifying potential human carcinogens. Benzene-induced sarcomas, p-cresidine-induced bladder carcinomas and phenolphthalein-induced thymic lymphomas were allelotyped at the Trp53 locus and chromosome 11 simple sequence length polymorphic (SSLP) loci. Loss of Trp53 and loss of one copy of chromosome 11 occurred in each of 10 lymphomas examined and each of the eight sarcomas examined. Loss of Trp53 and loss of heterozygosity (LOH) at SSLP loci were sporadic in the bladder carcinomas. However, LOH was detected at two or more SSLP loci in six of the eight bladder tumors examined. Loss of one complete copy of chromosome 11 was implicated in three of the bladder tumors where LOH occurred at seven or more widely dispersed SSLP loci. Loss of one copy of chromosome 11 likely occurred through a p53-mediated selection process since Trp53 is located on mouse chromosome 11 and only one copy harbored a functional gene. The data suggest that loss occurred through a mechanism common among the three tumor types. Allelotype patterns of the maternal chromosome 11 were inconsistent with those expected from a nullizygous C57BL/6-Trp53 (N4) x inbred C57BL/6 cross which was reported for production of the mice under investigation. However, comparison with individual control tissues still allowed deduction of maternal chromosome loss. If the breeding protocols were carried out as described, the unexpected allelotype patterns observed in histologically normal tissues might be due to mitotic homologous recombination during embryogenesis.

Alleles↗
PubMed2005

Screening procedure for detection of stimulant laxatives and/or their metabolites in human urine using gas chromatography-mass spectrometry after enzymatic cleavage of conjugates and extractive methylation.

A gas chromatography-mass spectrometry (GC-MS)-based screening procedure was developed for the detection of stimulant laxatives and/or their metabolites in human urine after enzymatic cleavage of conjugates followed by extractive methylation. The part of the phase-transfer catalyst remaining in the organic phase was removed by solid-phase extraction on a diol phase. The compounds were separated by capillary GC and identified by computerized MS in the full scan mode. By use of mass chromatography with the ions m/z 305, 290, 335, 320, 365, 350, 311, 326, 271, and 346, the possible presence of stimulant laxatives and/or their metabolites could be indicated. The identity of positive signals in such mass chromatograms was confirmed by comparison of the peaks underlying full mass spectra with the reference spectra. This method allowed the detection of the diphenol laxatives bisacodyl, picosulfate, and phenolphthalein and of the anthraquinone laxatives contained in plant extracts and/or their metabolites in human urine samples. The overall recoveries of the stimulant laxatives and/or their metabolites ranged between 33% and 89% with a coefficient of variation of less than 15%, and the limits of detection ranged between 10 and 25 ng/mL (S/N 3) in the full scan mode. After ingestion of the lowest therapeutic dose of sodium picosulfate, its main metabolite, bisacodyl diphenol, was detectable in urine samples for 72 hours. After ingestion of the lowest therapeutic dose of a senna extract, the main metabolite of sennosides, rhein, was detectable in urine samples for 24 hours. This procedure is part of a systematic toxicological analysis procedure for acidic drugs and poisons with the modification of enzymatic cleavage of conjugates.

Anthraquinones↗
PubMed1982

Uptake, conjugation and transport of laxative diphenols by everted sacs of the rat jejunum and stripped colon.

Phenolphthalein (PHEN), desacetylbisacodyl (DES) and oxyphenisatin (OXY) were incubated with everted sacs of the rat jejunum and stripped descending colon; the mucosal and serosal fluid were analysed with respect to free and conjugated diphenol by means of HPLC. Conjugates were measured as the amount of free diphenol in completely hydrolyzed samples less the amount before hydrolysis. A study with double-sided administration of PHEN revealed that diphenol uptake from and conjugate output to both sides followed a rectilinear course for 15-90 min. A standard incubation time of 60 min. was chosen for the subsequent experiments, in which the diphenols were administered at the mucosal side at a low and a high concentration. Diphenol uptake, i.e. the amount of free diphenol administered less the amount recovered at the mucosal side, varied in an order (PHEN greater than DES greater than OXY) which seems to be inversely related to the order of water solubility of the compounds. Tissue accumulation and conjugate output relative to uptake varied with the dose, and from one compound to another. At low initial concentration (20 nmol/ml), the compounds were transferred to the jejunal and colonic serosal fluid almost entirely as conjugates (greater than or equal to 95%); the transfer rates followed, qualitatively, the same order as above. In jejunum, more conjugates were released to the mucosal than to the serosal side; in colon the distribution was reversed. Increasing the dose to 100 nmol/ml caused a corresponding increase in uptake, but relative output decreased and tissue accumulation increased; thus demonstrating capacity limitation. With PHEN, the ratio of conjugated:free diphenol on the serosal side remained essentially unchanged; with DES in particular, but also with OXY the ratio decreased. These findings may be interpreted to mean that in case of PHEN capacity limitation is linked to conjugate efflux, while DES and OXY may be poor substrates for glucuronide formation as well. Experiments with serosal side administration like the double-sided PHEN experiments verified the dissimilar conjugate distribution in jejunal and colonic sacs; the phenomenon is to some extent discussed in the text. Identity tests gave evidence that the conjugates were mainly monoglucuronides.

Animals↗
PubMed1960

Mammalian liver beta-glucuronidase for hydrolysis of steroidal conjugates.

Although the rate of hydrolysis by mammalian beta-glucuronidase appears to be inhibited by methylene chloride or carbon tetrachloride with the standard technique (phenolphthalein glucuronide as a substrate), the release of steroidal conjugates under conditions generally employed does not appear to be affected.

17-Ketosteroids↗
PubMed1973

Phosphatase activity among Candida species and other yeasts isolated from clinical material.

A group of 277 yeasts isolated from burned children and 14 reference strains were tested for phosphatase activity by using phenolphthalein phosphate substrates. Phosphatase activity was widely distributed among various species and strains representing seven genera. Candida albicans, which was the most common yeast isolated from clinical material, was notably absent in producing the enzyme, whereas Candida tropicalis was the most consistent, strong, and rapidly active phosphatase-producing organism. The characteristic enzyme activity of a selected isolate of C. tropicalis was demonstrated in the presence of concentrations of inorganic phosphate which inhibited enzyme activity of other species. The greater enzyme activity of C. tropicalis was not related to more rapid or greater cell growth or decrease in the pH of culture media. Extracellular constitutive heat-labile acid phosphatase was found in broth filtrates of C. tropicalis, C. krusei, and a strain of Staphylococcus aureus.

Acid Phosphatase↗
PubMed1961

The antithrombin activity of glucuronic esters of bilirubin.

The plasma of patients with pronounced jaundice as well as that of cats with experimental obstructive jaundice inhibits the clotting of normal plasma with thrombin. The influence of different bile constituents-bilirubin, bilirubin glucuronides, sodium salts of bile acid-on the clotting of plasma or fibrinogen with thrombin was examined. Bilirubin glucuronides in concentrations above 8 mg.% showed antithrombic activity but other substances were inactive. Glucuronic acid and phenolphthalein glucuronide in concentrations up to 100 mg.% did not have any influence on the thrombin time.

Animals↗
PubMed1979

Detection of bacterial phosphatase activity by means of an original and simple test.

A new test for the detection of bacterial phosphatase activity has been devised. The test is performed using agar media containing both methyl green (MG) and phenolphthalein diphosphate (PDP); in these media phosphatase-producing strains grow deep-green-stained colonies whereas non-producing strains do not. A total of 739 different strains were tested, including 593 staphylococci, 95 micrococci, 11 streptococci, 10 corynebacteria, 14 enterobacteria, and 16 candidae. All strains found phosphatase-positive according to the conventional phosphatase test displayed deep-green-stained colonies on MG-PDP media, whereas all phosphatase-negative strains showed unstained colonies on the same media. The main advantages of the present phosphatase test as compared with other conventional ones are that it is more simple to perform, it can reveal the phosphatase activity of colonies grown in deep agar, and can be incorporated into commercial multitest kits.

Bacteria↗
PubMed1975

A model for the mode of action of cytochalasin B inhibition of D-glucose transport in the human erythrocyte.

By an optical method, cytochalasin B is shown to be a competitive inhibitor of D-glucose transport across the human erythrocyte membrane with Ki of 1.2 x 10(-7) M. A Drieding molecular model of cytochalasin B reveals an almost identical spatial distribution of four oxygen atoms to those found in the C1-conformation of beta-D-glucopyranose and implicated in hydrogen bonding to the carrier protein associated with D-glucose transport. The stereochemistry of this transport model is discussed. On the basis of the interoxygen distances found in cytochalasin B, hydrocortisone, prednisolone, corticosterone, and phenolphthalein are considered as analogues and are shown to be competitive inhibitors of D-glucose transport with Ki values of 2.2 x 10(-4) M, 3.0 x 10(-4) M, 4.0 x 10(-4) M, and 2.5 x 10(-5) M, respectively. These results are considered to be consistent with the proposed mode of action of cytochalasin B and also provide further support for the model of D-glucose stereospecifically hydrogen-bonded to a carrier protein.

Binding Sites↗
PubMed1985

Human hepatic beta-glucuronidase: an enzyme kinetic study.

beta-Glucuronidase (EC 3.2.1.31) was purified from human liver and its activity was determined by enzyme kinetic method employing phenolphthalein glucuronic acid (PGA) and conjugated bilirubin, primarily bilirubin diglucuronide purified from human bile, as substrates in the absence or presence of D-glucaro-1,4-lactone. The enzyme was capable of acting on both PGA and conjugated bilirubin with Michaelis constants of 0.435 mmol/l at 56 degrees C and 1.02 mmol/l at 37 degrees C, respectively. Both reactions were beta-glucuronidase-specific because both were inhibited by D-glucaro-1,4-lactone in a competitive fashion. Conjugated bilirubin acted as a noncompetitive inhibitor of the enzyme for PGA in a two-substrate system. The study indicates that these two substrates bind at different catalytic sites of the enzyme and, on molar base, conjugated bilirubin had higher affinity for the enzyme and less degree of inhibition by D-glucaro-1,4-lactone than PGA. Whether such catalytic sites are also common for other beta-D-glucuronid ethers and esters remains to be proven.

Bilirubin↗
PubMed1997

[Differences between phthaleins and sulfonphthaleins].

Differences in color and molecular structure between phthalein-pigments and sulfonphthalein-pigments were investigated using X-ray crystallography and absorption spectrophotometry of their aqueous solutions. The molecular structure of sulfonefluorescein (H2+SF-) was determined as a zwitter ion, 2-(3-hydroxonio-6-hydroxy-3H-xanthen-9-yl)benzenesulfonate. The absorption spectra of H2+SF- demonstrated the dissociation profile of a dibasic acid, while those of fluorescein (H2FL) indicated a tribasic acid and further, at pH > 10, SF2- and FL2-, while at pH < 0, H2+SF- and H3+FL to be dominant. The spectra of H2+SF- were analyzed to obtain the values of pK1 and pK2 together with the spectrum of HSF-. Similarly, from the spectra of H3+FL the values of pK1, pK2 and pK3 together with the spectra of HFL- and H2FL were obtained. Further by adding 1/5 of the H3+FL spectrum to 2/15 of HFL- spectrum, an indicated spectrum as that of H2FL was obtained. From these results, the features of dissociation of H2SF- and H3+FL were estimated. The molecular structure of phenolsulfonphtalein (H2PS-) was determined as a zwitter-ion, alpha-(4-hydroxonio-2,5-cyclohexadiene-1-ylidene)-alpha- (4-hydroxyphenyl)-2-toluenesulfonate. The absorption spectra of H2PS- demonstrated that H2PS-, HPS- and PS2- became dominant at pH << 0, pH = 4 and pH > 11, respectively. On the contrary, phenolphthalein (H2PP) displayed only one type of absorption spectrum in the visual region, the shape of which was similar to that of PS2- while the molar extinction coefficient was smaller. The spectra were analyzed to obtain the values of pK1 = 9.05 and pK2 = 9.50. The spectra also demonstrated a slow addition reaction of OH- to PP2- and pK3 = 12 was obtained by measuring the absorbance after equilibration. From these results, the features of dissociation and coloration of H2+PS- and H2PP were estimated.

Color↗
PubMed2006

Sequential injection titration with spectrophotometric detection for the assay of acidity in fruit juices.

A simple sequential injection analysis (SIA) with spectrophotometric detection for an assay of acidity in fruit juice was investigated. An alkaline reagent (sodium hydroxide), a sample and an indicator (phenolphthalein) were first aspirated and stacked as adjacent zones in a holding coil. With flow reversal through a reaction coil to the detector, zone penetration occurred, leading to a neutralization reaction that caused a decrease in the color intensity of the indicator being monitored for absorbance at 552 nm. The effects of various parameters were studied. Linear calibration graphs for acidities of 0.2 - 1.0 and 0.5 - 2.5% w/v citric acid as a standard, with a relative standard deviation of 1% (acidity of 0.3 - 0.6% w/v as citric acid, n=11) and a sample throughput of 30 samples h(-1), were achieved. The developed method was validated by a standard titrimetric method for assaying the acidity of fruit juice samples.

Beverages↗
PubMed2003

Possible mechanism on enhanced carcinogenesis of genotoxic carcinogens and unsolved mechanisms on lesser carcinogenic susceptibility to some carcinogens in rasH2 mice.

The rasH2 mice are hemizygous transgenic mice carrying the human prototype c-Ha-ras gene with its own promoter region, and have been used in 6-month short-term carcinogenicity tests for pharmaceutical drugs in accordance with the recommendation of the International Conference on Harmonization of Technical Requirements of Pharmaceuticals for Human Use (ICH). Based on the validation studies, it has been recognized that they are very susceptible to genotoxic carcinogens. To elucidate the mechanism of the enhanced carcinogenesis, spontaneous and chemically induced tumors in rasH2 mice have been subjected to molecular analyses, but the results have thus far been equivocal. This article focuses on the possible molecular mechanism of enhanced carcinogenesis in rasH2 mice, based on the results of a search in the literature. In addition, there are several reports suggesting lesser carcinogenic susceptibility of rasH2 mice to some carcinogens: Malignant lymphomas were induced by treatment with phenolphthalein in heterozygous p53 knockout mice, but not in rasH2 mice, and ethinylestradiol, uterine tumor promoter, resulted in depression of uterine proliferative lesions in rasH2 mice. In this review, the possible mechanisms of why rasH2 mice were less sensitive for these carcinogens are also discussed.

Animals↗
PubMed1984

Depression of glucuronyltransferase activity by glucocorticoids in adult female mice.

Three experiments were conducted to examine the effect of glucocorticoids on glucuronidation in the adult female mouse. In the first experiment, four mice served as controls, while four other mice were each given 80 micrograms triamcinolone acetonide (TA) at 39, 25, 15 and 1 h before they were killed. Liver homogenates from all animals were assayed for activity of uridine diphospho-glucuronyltransferase (UDP-GT). The mean enzymatic activity was 115 and 58 nmol of rho-nitrophenol conjugated to glucuronic acid X h-1 X mg of hepatic protein-1 for control and TA-treated mice, respectively (P less than .01). In Exp. 2, 48 mice were divided randomly into 12 groups, with four groups of controls, and four each treated with either 100 micrograms TA or 100 micrograms dexamethasone (DEX) at -4 and 0 h. All of the mice were given 2.5 mmol phenolphthalein (P) at 0 h. The excretion of free P was similar for all groups: however, mice treated with TA or DEX excreted significantly less P-glucuronide and mice treated with TA excreted significantly less P-sulfate than did the controls. In the third experiment, 30 mice each served as controls or were treated with 80 micrograms TA or 500 micrograms metyrapone (M) at -4 and 0 h. Also at 0 h, animals were given .12, .15, .19, .24 or .29 mg rho-cresol/g of body weight. The LD50 of rho-cresol for the control, TA- and M-treated groups were .19, .15 and .24 mg of rho-cresol/g of body weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1975

Surreptitious laxative ingestion. Delayed recognition of a serious condition: a case report.

A 46-year-old man with chronic diarrhea underwent exhaustive investigations, including laparotomy, but a definitive diagnosis could not be made. It was not until a colonoscopic biopsy demonstrated the pigment of melanosis coli that the surreptitious use of laxatives was considered seriously. This diagnosis was confirmed by simple chemical tests that demonstrated phenolphthalein in the feces and urine.

Cathartics↗
PubMed2002

Point mutations and deletions in the znfn1a1/ikaros gene in chemically induced murine lymphomas.

The Znfn1a1 gene encodes a zinc finger protein called Ikaros, which is criticalfor T-cell development and differentiation. The execution of normal function of Ikaros requires sequence-specific DNA binding, transactivation, and dimerization domains. In this study, exons 3-5 and exon 7 of the Znfn1a1 gene that encode the functional domains of Ikaros were analyzed for point mutations and deletions in murine lymphomas induced by 1,3-butadiene, 2',3'-dideoxycytidine, or phenolphthalein. Missense and frameshift mutations were identified in 11% (11 of 104) of the tumors. Interestingly, 8 of the mutations were identified in the NH2-terminal zinc finger motifs, which are crucial for the DNA-binding function of Ikaros. The other 3 samples carried frameshift mutations in exon 7 that resulted in truncations and abrogation of both transactivation and dimerization domains. One tumor with a missense mutation in the DNA-binding domain also displayed a 45-bp deletion in the dimerization domain. Southern analysis disclosed interstitial homozygous deletions in the functional domains of Ikaros in 4% (3 of 68) of the lymphomas examined. Allelic losses on markers surrounding the Znfn1a1 gene were detected in 27% (12 of 45) of the tumors analyzed. However, only 2 tumors with allelic losses also showed mutations in the Znfn1a1 gene, indicating that other tumor suppressor genes located on this region might be involved as well. Our results suggest inactivation of Ikaros in a subset of chemically induced lymphomas and additionally support the contention of tumor-suppressor activity for Ikaros.

Alleles↗