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1.
Comp Biochem Physiol C Toxicol Pharmacol ; 283: 109962, 2024 Jun 16.
Article in English | MEDLINE | ID: mdl-38889874

ABSTRACT

Tizoxanide (TZX) is an active metabolite of nitazoxanide (NTZ) originally developed as an antiparasitic agent, and is predominantly metabolized into TZX glucuronide. In the present study, TZX glucuronidation by the liver and intestinal microsomes of humans, monkeys, dogs, rats, and mice, and recombinant human UDP-glucuronosyltransferase (UGT) were examined. The kinetics of TZX glucuronidation by the liver and intestinal microsomes followed the Michaelis-Menten or biphasic model, with species-specific variations in the intrinsic clearance (CLint). Rats and mice exhibited the highest CLint values for liver microsomes, while mice and rats were the highest for intestinal microsomes. Among human UGTs, UGT1A1 and UGT1A8 demonstrated significant glucuronidation activity. Estradiol and emodin inhibited TZX glucuronidation activities in the human liver and intestinal microsomes in a dose-dependent manner, with emodin showing stronger inhibition in the intestinal microsomes. These results suggest that the roles of UGT enzymes in TZX glucuronidation in the liver and small intestine differ extensively across species and that UGT1A1 and/or UGT1A8 mainly contribute to the metabolism and elimination of TZX in humans. This study presents the relevant and novel-appreciative report on TZX metabolism catalyzed by UGT enzymes, which may aid in the assessment of the antiparasitic, antibacterial, and antiviral activities of NTZ for the treatment of various infections.

2.
Arch Toxicol ; 98(3): 837-848, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38182911

ABSTRACT

Tetrabromobisphenol A (TBBPA) and tetrachlorobisphenol A (TCBPA), bisphenol A (BPA) analogs, are endocrine-disrupting chemicals predominantly metabolized into glucuronides by UDP-glucuronosyltransferase (UGT) enzymes in humans and rats. In the present study, TBBPA and TCBPA glucuronidation by the liver microsomes of humans and laboratory animals (monkeys, dogs, minipigs, rats, mice, and hamsters) and recombinant human hepatic UGTs (10 isoforms) were examined. TBBPA glucuronidation by the liver microsomes followed the Michaelis-Menten model kinetics in humans, rats, and hamsters and the biphasic model in monkeys, dogs, minipigs, and mice. The CLint values based on the Eadie-Hofstee plots were mice (147) > monkeys (122) > minipigs (108) > humans (100) and rats (98) > dogs (81) > hamsters (47). TCBPA glucuronidation kinetics by the liver microsomes followed the biphasic model in all species except for minipigs, which followed the Michaelis-Menten model. The CLint values were monkeys (172) > rats (151) > mice (134) > minipigs (104), dogs (102), and humans (100) > hamsters (88). Among recombinant human UGTs examined, UGT1A1 and UGT1A9 showed higher TBBPA and TCBPA glucuronidation abilities. The kinetics of TBBPA and TCBPA glucuronidation followed the substrate inhibition model in UGT1A1 and the Michaelis-Menten model in UGT1A9. The CLint values were UGT1A1 (100) > UGT1A9 (42) for TBBPA glucuronidation and UGT1A1 (100) > UGT1A9 (53) for TCBPA glucuronidation, and the activities at high substrate concentration ranges were higher in UGT1A9 than in UGT1A1 for both TBBPA and TCBPA. These results suggest that the glucuronidation abilities toward TBBPA and TCBPA in the liver differ extensively across species, and that UGT1A1 and UGT1A9 expressed in the liver mainly contribute to the metabolism and detoxification of TBBPA and TCBPA in humans.


Subject(s)
Chlorophenols , Liver , Microsomes, Liver , Polybrominated Biphenyls , Humans , Animals , Rats , Mice , Dogs , Swine , Swine, Miniature/metabolism , Microsomes, Liver/metabolism , Liver/metabolism , Glucuronosyltransferase/metabolism , Animals, Laboratory/metabolism , Protein Isoforms/metabolism , Haplorhini/metabolism , Kinetics , Glucuronides/metabolism , Uridine Diphosphate/metabolism
3.
J Toxicol Sci ; 48(1): 37-45, 2023.
Article in English | MEDLINE | ID: mdl-36599426

ABSTRACT

Transient Receptor Potential Ankyrin 1 (TRPA1), which is expressed in the airways, has causative and exacerbating roles in respiratory diseases. TRPA1 is known as a target of sick building syndrome-related air pollutants, such as formaldehyde. Thus, an in vitro TRPA1 activation assay would be useful for predicting the potential risk of air pollution. In this study, we used human TRPA1 (hTRPA1)- and mouse TRPA1 (mTRPA1)-expressing cell lines to measure TRPA1 activation by the emerging indoor air pollutants 2-ethyl-1-hexanol (2-EH), a mixture of 2,2,4-trimethyl-1,3-pentanediol 1- and 3-monoisobutyrate (Texanol), and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB). The results indicated that 2-EH activated both hTRPA1 and mTRPA1 in a concentration-dependent manner, whereas TXIB did not activate hTRPA1 or mTRPA1. Texanol also activated hTRPA1 in a concentration-dependent manner. In contrast, a bell-shaped concentration-dependent curve was observed for mouse TRPA1 activation by Texanol, indicating inhibitory effects at a higher concentration range, which was also reported for menthol, a typical TRPA1 modulator. To further elucidate the mechanism underlying the species difference in TRPA1 activation by Texanol, V875G and G878V mutations were introduced into hTRPA1 and mTRPA1, respectively, which were reported to be key mutations for the inhibitory effect of menthol. These mutations switched the inhibitory effects of Texanol; thus, hTRPA1/V875G, but not mTRPA1/G878V, was inhibited at higher concentrations of Texanol. These results indicate that Texanol shares an interaction site with menthol. Overall, these findings suggest that careful interpretation is necessary when extrapolating rodent TRPA1-dependent toxicological effects to humans, especially with respect to the risk assessment of indoor air pollutants.


Subject(s)
Air Pollutants , Air Pollution, Indoor , Humans , Mice , Animals , Air Pollution, Indoor/adverse effects , Air Pollution, Indoor/analysis , Menthol , Species Specificity , Air Pollutants/toxicity , TRPA1 Cation Channel/genetics
4.
Chem Biol Interact ; 372: 110353, 2023 Feb 25.
Article in English | MEDLINE | ID: mdl-36657734

ABSTRACT

Phthalates are widely used plasticizers that are primarily and rapidly metabolized to monoester phthalates in mammals. In the present study, the hydrolysis of dibutyl phthalate (DBP) and di(2-ethylhexyl) phthalate (DEHP) in the human liver, small intestine, kidney, and lung was examined by the catalytic, kinetic, and inhibition analyses using organ microsomal and cytosolic fractions and recombinant carboxylesterases (CESs). The Vmax (y-intercept) values based on the Eadie-Hofstee plots of DBP hydrolysis were liver > small intestine > kidney > lung in microsomes, and liver > small intestine > lung > kidney in cytosol, respectively. The CLint values (x-intercept) were small intestine > liver > kidney > lung in both microsomes and cytosol. The Vmax and CLint or CLmax values of DEHP hydrolysis were small intestine > liver > kidney > lung in both microsomes and cytosol. Bis(4-nitrophenyl) phosphate (BNPP) effectively inhibited the activities of DBP and DEHP hydrolysis in the microsomes and cytosol of liver, small intestine, kidney, and lung. Although physostigmine also potently inhibited DBP and DEHP hydrolysis activities in both the microsomes and cytosol of the small intestine and kidney, the inhibitory effects in the liver and lung were weak. In recombinant CESs, the Vmax values of DBP hydrolysis were CES1 (CES1b, CES1c) > CES2, whereas the CLmax values were CES2 > CES1 (CES1b, CES1c). On the other hand, the Vmax and CLmax values of DEHP hydrolysis were CES2 > CES1 (CES1b, CES1c). These results suggest an extensive organ-dependence of DBP and DEHP hydrolysis due to CES expression, and that CESs are responsible for the metabolic activation of phthalates.


Subject(s)
Dibutyl Phthalate , Diethylhexyl Phthalate , Animals , Humans , Carboxylic Ester Hydrolases/metabolism , Diethylhexyl Phthalate/pharmacology , Hydrolysis , Liver/metabolism , Intestine, Small/metabolism , Microsomes/metabolism , Kidney/metabolism , Lung/metabolism , Mammals/metabolism
5.
Biol Pharm Bull ; 45(12): 1839-1846, 2022 Dec 01.
Article in English | MEDLINE | ID: mdl-36223942

ABSTRACT

Phthalic acid (PA) diesters are widely used in consumer products, as plasticizers, and are ubiquitous environmental pollutants. There is a growing concern about their adjuvant effect on allergic diseases. Although its precise mechanism remains unknown, possible involvement of transient receptor potential ankyrin 1 (TRPA1) has been suggested. Hence, in this study, the activation of human and mouse TRPA1s by a series of PA di- and monoesters was investigated using a heterologous expression system in vitro. Consequently, it was found that monoesters activated human TRPA1, where EC50 values were in the order of mono-hexyl > mono-heptyl > mono-n-octyl > mono-2-ethylhexyl > mono-isononyl and mono-isodecyl esters. Significant species differences in TRPA1 activation by PA monoesters were also discovered; PA monoesters activated human TRPA1 but not mouse TRPA1 in a concentration-dependent manner up to 50 µM. These findings suggest that PA esters may exert TRPA1-dependent adverse effects on humans, which have never been demonstrated in experimental animals.


Subject(s)
Phthalic Acids , TRPA1 Cation Channel , Animals , Humans , Phthalic Acids/toxicity , Plasticizers , Species Specificity , Mice , TRPA1 Cation Channel/metabolism
6.
Biol Pharm Bull ; 45(8): 1116-1123, 2022.
Article in English | MEDLINE | ID: mdl-35908893

ABSTRACT

Flavones, which are distributed in a variety of plants and foods in nature, possess significant biological activities, including antitumor and anti-inflammatory effects, and are metabolized into glucuronides by uridine 5'-diphosphate (UDP)-glucuronosyltransferase (UGT) enzymes in humans. In this study, apigenin, acacetin, and genkwanin, flavones having hydroxyl groups at C5, C7, and/or C4'positions were focused on, and the regioselective glucuronidation in human liver and intestinal microsomes was examined. Two glucuronides (namely, AP-7G and AP-4'G for apigenin, AC-5G and AC-7G for acacetin, and GE-5G and GE-4'G for genkwanin) were formed from each flavone by liver and intestinal microsomes, except for only GE-4'G formation from genkwanin by intestinal microsomes. The order of total glucuronidation activities was liver microsomes > intestinal microsomes for apigenin and acacetin, and liver microsomes < intestinal microsomes for genkwanin. The order of CLint values (x-intercept) based on v versus V/[S] plots for apigenin glucuronidation was AP-7G > AP-4'G in liver microsomes and AP-7G < AP-4'G in intestinal microsomes. The order of CLint values was AC-5G < AC-7G for acacetin and GE-5G < GE-4'G genkwanin glucuronidation in both liver and intestinal microsomes. This suggests that the abilities and roles of UGT enzymes in the glucuronidation of apigenin, acacetin, and genkwanin in humans differ depending on the chemical structure of flavones.


Subject(s)
Apigenin , Flavones , Microsomes , Glucuronides/metabolism , Glucuronosyltransferase/metabolism , Humans , Intestines/metabolism , Liver/metabolism , Microsomes/metabolism , Microsomes, Liver/metabolism
7.
Biol Pharm Bull ; 45(8): 1185-1190, 2022.
Article in English | MEDLINE | ID: mdl-35908900

ABSTRACT

Bitter taste receptors (TAS2Rs) are expressed by oral cavity cells in mammals and classically function as sensors for bitter compounds. There are 25 functional isoforms of human TAS2Rs, with individual bitter ligands. Each human TAS2R isoform is distributed in several tissues, such as the airway epithelia and gastrointestinal tract, and plays an important role in physiological functions. However, quantification of each isoform is difficult because of highly homologous sequences between some TAS2R isoforms. Therefore, differentiating the isoforms by their expression levels is suitable for clarifying the tissue-specific effects of bitter compounds. In this study, we developed a real-time quantitative PCR (qPCR) method to determine the expression of each TAS2R isoform. Using plasmid standards harboring each isoform, we confirmed that the current assay can quantify the gene expression of each isoform, with negligible interference from other isoforms. In addition, our methods can successfully discriminate between the mRNA expression of each isoform in human cell lines and tissues. Therefore, this qPCR method can successfully quantify the mRNA level of each TAS2R isoform. This method will contribute to a better understanding of the molecular mechanisms underlying the TAS2R ligand-activated signal transduction.


Subject(s)
Protein Isoforms , Receptors, G-Protein-Coupled , Taste , Animals , Humans , Ligands , Protein Isoforms/genetics , RNA, Messenger , Real-Time Polymerase Chain Reaction , Receptors, G-Protein-Coupled/genetics , Receptors, G-Protein-Coupled/metabolism , Transcription, Genetic
8.
Drug Chem Toxicol ; 45(4): 1565-1569, 2022 Jul.
Article in English | MEDLINE | ID: mdl-33187449

ABSTRACT

Bisphenol A (BPA) is an endocrine-disrupting chemical, and is predominantly metabolized into glucuronide in mammals. The present study was conducted in order to examine the hepatic and intestinal glucuronidation of BPA in humans and laboratory animals such as monkeys, dogs, rats, and mice in an in vitro system using microsomal fractions. Km, Vmax, and CLint values in human liver microsomes were 7.54 µM, 17.7 nmol/min/mg protein, and 2.36 mL/min/mg protein, respectively. CLint values in liver microsomes of monkey, dogs, rats, and mice were 1.5-, 2.4-, 1.7- and 8.2-fold that of humans, respectively. In intestinal microsomes, Km, Vmax, and CLint values in humans were 39.3 µM, 0.65 nmol/min/mg protein, and 0.02 mL/min/mg protein, respectively. The relative levels of CLint in monkey, dogs, rats, and mice to that of humans were 7.0-, 12-, 34-, and 29-fold, respectively. Although CLint values were higher in liver microsomes than in intestinal microsomes in all species, and marked species difference in the ratio of liver to intestinal microsomes was observed as follows: humans, 118; monkeys, 25; dogs, 23; rats, 5.9; mice, 33. These results suggest that the functional roles of UDP-glucuronosyltransferase (UGT) enzymes expressed in the liver and intestines in the metabolism of BPA extensively differ among humans, monkeys, dogs, rats, and mice.


Subject(s)
Intestinal Mucosa , Microsomes , Animals , Animals, Laboratory , Benzhydryl Compounds , Dogs , Humans , Intestinal Mucosa/metabolism , Intestines , Liver/metabolism , Macaca fascicularis , Mammals , Mice , Microsomes/metabolism , Microsomes, Liver , Phenols , Rats , Species Specificity
9.
Drug Metab Dispos ; 50(1): 17-23, 2022 01.
Article in English | MEDLINE | ID: mdl-34670778

ABSTRACT

Pharmacokinetic prediction after oral ingestion is important for quantitative risk assessment of food-derived compounds. To evaluate the utility of human intestinal absorption prediction, we compared the membrane permeability and metabolic activities of human induced pluripotent stem cell-derived small intestinal epithelial cells (hiPSC-SIECs) with Caco-2 cells or human primary enterocytes (hPECs). We found that membrane permeability in hiPSC-SIECs had better predictivity than that in Caco-2 cells against 21 drugs with known human intestinal availability (r = 0.830 and 0.401, respectively). Membrane permeability in hiPSC-SIECs was only 0.019-0.25-fold as compared with that in Caco-2 cells for 7 in 15 food-derived compounds, primarily those that were reported to undergo glucuronidation metabolism. The metabolic rates of the glucuronide conjugate were similar or higher in hiPSC-SIECs as compared with hPECs but lower in Caco-2 cells. Expression levels of UDP-glucuronosyltransferase (UGT) isoform mRNA in hiPSC-SIECs were similar or higher as compared with hPECs. Therefore, hiPSC-SIECs could be a useful tool for predicting human intestinal absorption to simultaneously evaluate membrane permeability and UGT-mediated metabolism. SIGNIFICANCE STATEMENT: Gastrointestinal absorption is an important step for predicting the internal exposure of food-derived compounds. This research revealed that human induced pluripotent stem cell-derived small intestinal cells (hiPSC-SIECs) had better predictivity of intestinal availability than Caco-2 cells; furthermore, the metabolic rates of UDP-glucuronosyltransferase (UGT) substrates of hiPSC-SIECs were closer to those of human primary enterocytes than those of Caco-2 cells. Therefore, hiPSC-SIECs could be a useful tool for predicting human intestinal absorption to simultaneously evaluate membrane permeability and UGT-mediated metabolism.


Subject(s)
Cell Membrane Permeability , Epithelial Cells/metabolism , Glucuronosyltransferase/metabolism , Induced Pluripotent Stem Cells/metabolism , Intestine, Small/metabolism , Caco-2 Cells , Erythrocytes/metabolism , Food , Glucuronides/metabolism , Humans , Intestinal Absorption , Intestine, Small/cytology , Pharmaceutical Preparations/metabolism , Predictive Value of Tests
10.
Biopharm Drug Dispos ; 42(5): 218-225, 2021 May.
Article in English | MEDLINE | ID: mdl-33754379

ABSTRACT

Favipiravir is an antiviral agent effective against several RNA viruses that is converted into an inactive oxidative metabolite (M1), mainly by aldehyde oxidase, in humans. In the present study, the biotransformation of favipiravir into M1 in male and female humans, monkeys, rats, and mice was examined in an in vitro system using liver cytosolic fractions. The kinetics for M1 formation followed the Michaelis-Menten model in all species. The Km , Vmax , and CLint values in humans were 602 µM, 466 pmol/min/mg protein, and 776 nl/min/mg protein in males, respectively, and 713 µM, 404 pmol/min/mg protein, and 567 nl/min/mg protein in females, respectively. Species differences in CLint values were monkeys > humans > mice > rats in both males and females, and the variations for males and females were 120- and 96-fold, respectively. Sex differences in CLint values were males > females in humans and mice, females > males in monkeys and rats, and marked variation (4.3-fold) was noted in mice. This suggests that the roles of aldehyde oxidase in the hepatic metabolism of favipiravir differ extensively depending on the species and sex, and this study will aid in the assessment of the antiviral activities of favipiravir against novel and/or variant viruses.


Subject(s)
Amides/metabolism , Antiviral Agents/metabolism , Pyrazines/metabolism , Adolescent , Adult , Aged , Animals , Biotransformation , Child , Child, Preschool , Cytosol/metabolism , Female , Humans , Liver/metabolism , Macaca fascicularis , Male , Mice , Microsomes, Liver/metabolism , Middle Aged , Rats, Sprague-Dawley , Sex Characteristics , Species Specificity , Young Adult
11.
Xenobiotica ; 50(8): 906-912, 2020 Aug.
Article in English | MEDLINE | ID: mdl-32005083

ABSTRACT

Wogonin, one of the flavonoids isolated from Scutellaria baicalensis, exhibits some beneficial bioactivities, including anti-inflammatory and anticancer effects, and is metabolized into glucuronide by UDP-glucuronosyltransferase (UGT) enzymes in humans. In the present study, wogonin glucuronidation was examined in the liver and intestinal microsomes of humans, monkeys, dogs, rats, and mice using a kinetic analysis.The kinetics of wogonin glucuronidation by liver microsomes followed the biphasic model in all species examined. CLint values (x-intercept) based on v versus V/[S] plots were rats > humans ≈ monkeys > mice > dogs. The kinetics of intestinal microsomes fit the Michaelis-Menten model for humans, monkeys, rats, and mice and the substrate inhibition model for dogs. CLint values were rats > monkeys > mice > dogs > humans. The tissue dependence of CLint values was liver microsomes > intestinal microsomes for humans, dogs, and rats, and liver microsomes ≈ intestinal microsomes for monkeys and mice.These results demonstrated that the metabolic abilities of UGT enzymes toward wogonin in the liver and intestines markedly differ among humans, monkeys, dogs, rats, and mice, and suggest that species differences are closely associated with the biological effects of wogonin.


Subject(s)
Flavanones/metabolism , Plant Extracts/metabolism , Animals , Dogs , Glucuronides/metabolism , Glucuronosyltransferase/metabolism , Humans , Intestines , Kinetics , Liver/metabolism , Macaca fascicularis/metabolism , Mice , Microsomes, Liver/metabolism , Rats , Scutellaria baicalensis
12.
Food Chem Toxicol ; 131: 110542, 2019 Sep.
Article in English | MEDLINE | ID: mdl-31163218

ABSTRACT

S-equol, an active metabolite of the soy isoflavone daidzein, is mainly metabolized into glucuronide(s) by UDP-glucuronosyltransferase (UGT) enzymes in mammals. In the present study, S-equol glucuronidation was examined in the liver and intestinal microsomes of humans, monkeys, dogs, rats, and mice using a kinetic analysis. CLint values for 7- and 4'-glucuronidation by liver microsomes were higher than those by intestinal microsomes in all species. CLint values for total glucuronidation (sum of 7- and 4'-glucuronidation) were rats (7.6) > monkeys (5.8) > mice (4.9) > dogs (2.8) > humans (1.0) for liver microsomes, and rats (9.6) > mice (2.8) > dogs (1.3) ≥ monkeys (1.2) > humans (1.0) for intestinal microsomes, respectively. Regarding regioselective glucuronidation by liver and intestinal microsomes, CLint values were 7-glucuronidation > 4'-glucuronidation for humans, monkeys, dogs, and mice, and 4'-glucuronidation > 7-glucuronidation for rats. These results suggest that the metabolic abilities of UGT enzymes toward S-equol in the liver and intestines markedly differ among humans, monkeys, dogs, rats, and mice.


Subject(s)
Equol/metabolism , Glucuronides/biosynthesis , Microsomes, Liver/metabolism , Adolescent , Adult , Aged , Animals , Child , Child, Preschool , Dogs , Equol/chemistry , Glucuronosyltransferase/metabolism , Humans , Intestinal Mucosa/metabolism , Kinetics , Macaca fascicularis , Mice , Middle Aged , Rats, Sprague-Dawley , Stereoisomerism , Young Adult
13.
Toxicol In Vitro ; 54: 237-242, 2019 Feb.
Article in English | MEDLINE | ID: mdl-30315871

ABSTRACT

Di(2-ethylhexyl) phthalate (DEHP) is a widely used plasticizer that is rapidly metabolized to mono(2-ethylhexyl) phthalate (MEHP), an active metabolite, in mammals. In the present study, the hydrolysis of DEHP by the liver and intestinal microsomes of humans, monkeys, dogs, rats, and mice was examined. The kinetics of liver microsomes fit the Michaelis-Menten model for humans, monkeys, and rats, and the Hill model for dogs and mice. Km or S50 values were similar among species, whereas Vmax exhibited species differences of approximately 9-fold. CLint or CLmax values were in the order of mice > dogs > monkeys ≥ rats > humans. Hydrolytic activity towards DEHP was not detected in the intestinal microsomes of humans or dogs. The kinetics of monkeys, rats, and mice followed the Hill model. In comparisons of the liver microsomes of each species, S50 values were similar, while Vmax and CLmax values (mice > rats > monkeys) were considerably lower (approximately 5-25%). These results suggest that hydrolytic activity towards DEHP in the liver and intestines markedly differ among humans and non-rodent and rodent experimental animals, and imply that species differences are closely associated with the toxicity of DEHP.


Subject(s)
Diethylhexyl Phthalate/pharmacology , Intestines , Liver , Microsomes/metabolism , Plasticizers/pharmacology , Adolescent , Adult , Aged , Animals , Dogs , Humans , Hydrolysis , Macaca fascicularis , Mice , Middle Aged , Rats, Sprague-Dawley , Species Specificity , Young Adult
14.
Biol Pharm Bull ; 41(12): 1824-1829, 2018 Dec 01.
Article in English | MEDLINE | ID: mdl-30282851

ABSTRACT

Mohs paste (MP) is a hospital preparation containing zinc hydrochloride and zinc oxide starch. It is a topical medication used to fixate tissues for the removal of inoperable skin tumors and the management of hemorrhage and exudates, and to prevent foul odor resulting from secondary infections. However, it has problems, such as changes in hardness and viscoelasticity with time and liquefaction by exudate. It has been reported that the modified MP with D-sorbitol (S-MP) and the modified MP using the cellulose instead of starch (C-MP) have excellent physicochemical stability and better handling than original MP (O-MP). In this study, the effect of prescription improvement of MP on the pharmacological effect was examined with reference to water absorbing property, and its tumor tissue invasion fixation depth as an indicator. In the S-MP and C-MP, the amounts of water absorption did not differ significantly from those in the O-MP. The hardness of S-MP was decreased and liquefied like O-MP after absorbing water. In contrast, C-MP retained its form even after water absorption. The subcutaneous tumors in mice treated with modified MP formulations were measured for invasion fixation depth at 6 and 24 h after application. And the tissue status was observed using computed tomography. In all MPs, invasion fixation depth increased depending on application time. S-MP and O-MP depths did not differ significantly. The invasion depths of the C-MP significantly increased compared with those in the O-MP. These results suggest that C-MP had a high tissue fixation rate.


Subject(s)
Drug Compounding , Mohs Surgery , Neoplasms/metabolism , Tissue Adhesives/metabolism , Water/metabolism , Animals , Cell Line, Tumor , Cellulose/chemistry , Cellulose/metabolism , Chlorides/chemistry , Chlorides/metabolism , Drug Evaluation, Preclinical/methods , Female , Mice , Mice, Inbred ICR , Neoplasms/surgery , Starch/chemistry , Starch/metabolism , Tissue Adhesives/chemistry , Water/chemistry , Zinc Compounds/chemistry , Zinc Compounds/metabolism , Zinc Oxide/chemistry , Zinc Oxide/metabolism
15.
Arch Toxicol ; 92(9): 2809-2817, 2018 09.
Article in English | MEDLINE | ID: mdl-30014295

ABSTRACT

Daidzein, one of the major soy isoflavones, has a number of beneficial bioactivities for human health. It is mainly metabolized into 7- and/or 4'-glucuronides by UDP-glucuronosyltransferase (UGT) enzymes in mammals, including humans. The present study was conducted to examine the regioselective glucuronidation of daidzein at the 7- and 4'-hydroxyl groups in the liver and intestinal microsomes of humans, monkeys, rats, and mice. Daidzein glucuronidation activities at substrate concentrations of 1.0-200 µM were assessed, and Eadie-Hofstee plots were constructed. The kinetics for 7- and 4'-glucuronidation in the liver microsomes fit the Michaelis-Menten model, except for an atypical model for 7-glucuronidation in rats and a biphasic model for 4'-glucuronidation in monkeys. These kinetics in the intestinal microsomes followed the Michaelis-Menten model, except for a biphasic model for 7-glucuronidation in mice. The CLint values for 7-glucuronidation were in the order of monkeys (49) ≫ rats (5.3) > humans (1.0) > mice (0.7) for liver microsomes, and rats (2.4) ≥ monkeys (2.2) > humans (1.0) ≥ mice (0.8) for intestinal microsomes. On the other hand, the CLint values for 4'-glucuronidation were in the order of monkeys (4.0) > mice (1.0) ≈ humans (1.0) > rats (0.4) for liver microsomes, and humans (1.0) ≫ monkeys (0.08) ≥ mice (0.07) > rats (0.05) for intestinal microsomes. These results demonstrated that the metabolic abilities of UGT enzymes toward daidzein in the liver and intestines markedly differed among humans, monkeys, rats, and mice, and suggest that species and regioselective differences are closely associated with the bioactivities of soy isoflavones.


Subject(s)
Intestines/drug effects , Isoflavones/pharmacokinetics , Microsomes/drug effects , Adolescent , Adult , Aged , Animals , Glucuronosyltransferase/metabolism , Humans , Intestinal Mucosa/drug effects , Intestinal Mucosa/metabolism , Isoflavones/metabolism , Macaca fascicularis , Mice, Inbred Strains , Microsomes/metabolism , Microsomes, Liver/metabolism , Middle Aged , Rats, Sprague-Dawley
16.
Food Chem Toxicol ; 111: 417-422, 2018 Jan.
Article in English | MEDLINE | ID: mdl-29198856

ABSTRACT

Naringenin, a flavanone found in citrus fruits, is mainly metabolized into glucuronide(s) by UDP-glucuronosyltransferase (UGT) enzymes in mammals. In the present study, the glucuronidation of naringenin in the liver and intestine microsomes of humans, monkeys, rats, and mice was examined. The kinetics of 7-glucuronidation in human liver and intestine microsomes followed the Michaelis-Menten model. Kinetics in mouse liver and intestine microsomes also followed the Michaelis-Menten model, whereas those in monkey and rat liver microsomes fit the biphasic model. Kinetics in monkey and rat intestine microsomes fit the Michaelis-Menten and substrate inhibition models, respectively. CLint values were mice > monkeys > rats > humans for liver microsomes, and mice > rats > monkeys > humans for intestine microsomes. In 4´-glucuronidation, activities in human liver microsomes and monkey liver and intestine microsomes were negligible or very low. Kinetics in rat and mouse liver microsomes followed the biphasic and Michaelis-Menten models, respectively. CLint values were rats > mice for liver microsomes, and rats > mice > humans for intestine microsomes. These results suggest that the metabolic abilities and regioselectivity of UGT enzymes toward naringenin in the liver and intestines generally differ between primates and rodents.


Subject(s)
Flavanones/metabolism , Microsomes/metabolism , Animals , Humans , Intestinal Mucosa/metabolism , Liver/metabolism , Macaca fascicularis , Mice , Rats , Species Specificity
17.
Arch Toxicol ; 91(11): 3543-3550, 2017 Nov.
Article in English | MEDLINE | ID: mdl-28500425

ABSTRACT

4-tert-Octylphenol (4-tOP) is an endocrine-disrupting chemical. It is mainly metabolized into glucuronide by UDP-glucuronosyltransferase (UGT) enzymes in humans. The purpose of this study was to assess inter-individual variability in and the possible roles of UGT isoforms in hepatic 4-tOP glucuronidation in the humans. 4-tOP glucuronidation activities in the liver microsomes and recombinant UGTs of humans were assessed at broad substrate concentrations, and kinetics were analyzed. Correlation analyses between 4-tOP and diclofenac or 4-hydroxybiphenyl activities in pooled and individual human liver microsomes were also performed. Typical CLint values were 17.8 mL/min/mg protein for the low type, 25.2 mL/min/mg protein for the medium type, and 47.7 mL/min/mg protein for the high type. Among the recombinant UGTs (13 isoforms) examined, UGT2B7 and UGT2B15 were the most active of catalyzing 4-tOP glucuronidation. Although the K m values of UGT2B7 and UGT2B15 were similar (0.36 and 0.42 µM, respectively), the CLint value of UGT2B7 (6.83 mL/min/mg protein) >UGT2B15 (2.35 mL/min/mg protein). Strong correlations were observed between the glucuronidation activities of 4-tOP and diclofenac (a probe for UGT2B7) or 4-hydroxybiphenyl (a probe for UGT2B15) with 0.79-0.88 of Spearman correlation coefficient (r s) values. These findings demonstrate that 4-tOP glucuronidation in humans is mainly catalyzed by hepatic UGT2B7 and UGT2B15, and suggest that these UGT isoforms play important and characteristic roles in the detoxification of 4-tOP.


Subject(s)
Glucuronosyltransferase/metabolism , Liver/drug effects , Liver/metabolism , Phenols/pharmacokinetics , Adolescent , Adult , Aged , Biphenyl Compounds/metabolism , Biphenyl Compounds/pharmacokinetics , Diclofenac/pharmacokinetics , Endocrine Disruptors/pharmacokinetics , Female , Glucuronides/metabolism , Glucuronosyltransferase/genetics , Humans , Male , Microsomes, Liver/drug effects , Microsomes, Liver/metabolism , Middle Aged , Recombinant Proteins/genetics , Recombinant Proteins/metabolism
18.
Yakugaku Zasshi ; 137(4): 477-484, 2017.
Article in Japanese | MEDLINE | ID: mdl-28381726

ABSTRACT

Mohs paste is an external preparation containing zinc hydrochloride and zinc oxide starch as the main ingredient, and it is used for the palliative treatment of patients with surgically untreatable malignant tumors. However, it has problems, such as changes in hardness and viscoelasticity with time and liquefaction by exudate. To overcome these problems, we modified the formulation of Mohs paste by excluding starch, which is the cause of physical changes, and investigated the base. In the modified Mohs paste using the macrogol ointment for the base, no marked change with time was noted in the hardness, malleability, or elongation property, and the water-absorbing properties were equivalent to those of Mohs paste immediately after preparation. The hardness did not decrease even after absorbing water. The drug release rate increased 1.5 times with the modified Mohs paste. Based on these findings, the risk of liquefaction-associated damage of the surrounding skin decreased on using the modified Mohs paste, and preparing in advance became possible. These results suggest that the modified Mohs paste using the macrogol ointment for the base exhibits an equivalent effect for control of exudate and a high effect for tissue fixation.


Subject(s)
Chlorides , Drug Compounding/methods , Zinc Compounds , Zinc Oxide , Chemical Phenomena , Ointment Bases , Ointments , Polyethylene Glycols , Starch
19.
Arch Toxicol ; 91(3): 1227-1232, 2017 Mar.
Article in English | MEDLINE | ID: mdl-27405656

ABSTRACT

4-tert-Octylphenol (4-tOP) is an endocrine-disrupting chemical. It is mainly metabolized into glucuronide by UDP-glucuronosyltransferase (UGT) enzymes in mammals. In the present study, the glucuronidation of 4-tOP in humans, monkeys, rats, and mice was examined in an in vitro system using microsomal fractions. The kinetics of 4-tOP glucuronidation by liver microsomes followed the Michaelis-Menten model for humans and monkeys, and the biphasic model for rats and mice. The K m, V max, and CL int values of human liver microsomes were 0.343 µM, 11.6 nmol/min/mg protein, and 33.8 mL/min/mg protein, respectively. The kinetics of intestine microsomes followed the Michaelis-Menten model for humans, monkeys, and rats, and the biphasic model for mice. The K m, V max, and CL int values of human intestine microsomes were 0.743 µM, 0.571 nmol/min/mg protein, and 0.770 mL/min/mg protein, respectively. The CL int values estimated by Eadie-Hofstee plots were in the order of mice (high-affinity phase) (3.0) > humans (1.0) ≥ monkeys (0.9) > rats (high-affinity phase) (0.4) for liver microsomes, and monkeys (10) > mice (high-affinity phase) (5.6) > rats (1.4) > humans (1.0) for intestine microsomes. The percentages of the CL int values of intestine microsomes to liver microsomes were in the order of monkeys (27 %) > rats (high-affinity phase in liver microsomes) (7.9 %) > mice (high-affinity phase in liver and intestine microsomes) (4.2 %) > humans (2.3 %). These results suggest that the metabolic abilities of UGT enzymes expressed in the liver and intestine toward 4-tOP markedly differ among species and imply that species differences are strongly associated with the toxicities of alkylphenols.


Subject(s)
Microsomes/drug effects , Phenols/pharmacokinetics , Adolescent , Adult , Aged , Animals , Humans , Intestines/cytology , Macaca fascicularis , Mice, Inbred Strains , Microsomes/metabolism , Microsomes, Liver/drug effects , Microsomes, Liver/metabolism , Middle Aged , Phenols/metabolism , Rats, Sprague-Dawley , Species Specificity , Young Adult
20.
Arch Toxicol ; 91(2): 689-698, 2017 Feb.
Article in English | MEDLINE | ID: mdl-27071666

ABSTRACT

Mono(2-ethylhexyl) phthalate (MEHP) is an active metabolite of di(2-ethylhexyl) phthalate (DEHP), which is an endocrine-disrupting chemical. In the present study, MEHP glucuronidation in humans was studied using recombinant UDP-glucuronosyltransferases (UGTs) and microsomes of the liver and intestine. Among the recombinant UGTs examined, UGT1A3, UGT1A7, UGT1A8, UGT1A9, UGT1A10, UGT2B4, and UGT2B7 glucuronidated MEHP. The kinetics of MEHP glucuronidation by UGT1A3, UGT1A7, UGT1A8, UGT1A10, UGT2B4, and UGT2B7 followed the Michaelis-Menten model, whereas that by UGT1A9 fit the negative allosteric model. CLint values were in the order of UGT1A9 > UGT2B7 > UGT1A7 > UGT1A8 ≥ UGT1A10 > UGT1A3 > UGT2B4. The kinetics of MEHP glucuronidation by liver microsomes followed the Michaelis-Menten model. Diclofenac (20 µM) and raloxifene (20 µM) decreased CLint values to 43 and 36 % that of native microsomes, respectively. The kinetics of MEHP glucuronidation by intestine microsomes fit the biphasic model. Diclofenac (150 and 450 µM) decreased CLint values to 32 and 13 % that of native microsomes for the high-affinity phase, and to 28 and 21 % for the low-affinity phase, respectively. Raloxifene (2.5 and 7.0 µM) decreased CLint values to 35 and 4.1 % that of native microsomes for the high-affinity phase, and to 48 and 53 % for the low-affinity phase, respectively. These results suggest that MEHP glucuronidation in humans is catalyzed by UGT1A3, UGT1A9, UGT2B4, and/or UGT2B7 in the liver, and by UGT1A7, UGT1A8, UGT1A9, UGT1A10, and/or UGT2B7 in the intestine, and also that these UGT isoforms play important and characteristic roles in the detoxification of DEHP.


Subject(s)
Diethylhexyl Phthalate/analogs & derivatives , Glucuronosyltransferase/metabolism , Diclofenac/pharmacology , Diethylhexyl Phthalate/metabolism , Diethylhexyl Phthalate/pharmacokinetics , Endocrine Disruptors/metabolism , Endocrine Disruptors/pharmacokinetics , Glucuronosyltransferase/genetics , Humans , Intestinal Mucosa/metabolism , Intestines/drug effects , Microsomes/drug effects , Microsomes/metabolism , Microsomes, Liver/drug effects , Microsomes, Liver/metabolism , Models, Theoretical , Raloxifene Hydrochloride/pharmacology , Recombinant Proteins/genetics , Recombinant Proteins/metabolism
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