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OBJECTIVE: To investigate the metabolic characteristics of bakuchiol mediated by cytochrome P450 enzyme (CYP) and UDP-glucuronosyltransferase (UGT) in rat liver microsomes (RLMs) or human liver microsomes (HLMs), and to compare the metabolic gender differences. METHODS: Bakuchiol was incubated at 37? with male and female RLMs or HLMs in the presence of nicotinamide adenine dinucleotide phosphate (NADPH) or uridine 5′-diphosphoglucuronic acid (UDPGA). The residual concentrations of bakuchiol were measured in each incubation system using high performance liquid chromatography (HPLC). The metabolic stability and metabolic gender differences of bakuchiol were evaluated by the remaining percentage of bakuchiol after incubation.RESULTS: When bakuchiol was metabolized by CYP in RLMs, the intrinsic clearance (Clint) value in male RLMs ?(326.6±15.4) mL·min-1·kg-1?was significantly higher than that of female RLMs ?(77.2±4.8) mL·min-1·kg-1? (P<0.01). When bakuchiol was metabolized by UGT in RLMs, female RLMs had a significantly higher Clint value ?(419.1±24.1) mL·min-1·kg-1? than male RLMs ?(164.5±8.4) mL·min-1·kg-1? (P<0.01). When bakuchiol was metabolized by both CYP and UGT in RLMs, male RLMs had a significantly higher Clint value ?(1063.1±27.2) mL·min-1·kg-1? than female RLMs ?(781.2±16.5) mL·min-1·kg-1?(P<0.01). When bakuchiol was metabolized by CYP in HLMs, male HLMs had a significantly higher Clint value ?(24.8±2.1) mL·min-1·kg-1? than female HLMs ?(17.6±1.0) mL·min-1·kg-1? (P<0.01). There were no significant gender differences in the metabolism of bakuchiol when it was metabolized by UGT in HLMs. The Clint values were 176.4±26.5 and (165.9±8.6) mL·min-1·kg-1, respectively. The metabolic parameters of bakuchiol mediated by CYP and UGT in HLMs had no significant gender differences. The Clint values were 262.5±20.9 and (236.2±10.5) mL·min-1·kg-1, respectively. CONCLUSION Bakuchiol can be metabolized by CYP and UGT in RLMs or HLMs, and the metabolic parameters exhibit species differences and gender differences.
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UDP-glucuronosyltransferase (UGT), a kind of phase II drug-metabolizing enzyme, catalyzes the conjugation of glucuronic acid and drugs. UGTs are widely expressed in brain, but at a relatively low level compared to that in liver. Brain UGTs are inducible or inhibitable, which influences the drug distribution in the central nervous system. UGTs, cytochrome P450 (CYPs) and transporters act together to effect pharmacokinetics of drugs in brain. Several drugs have the capacity to cross the blood brain barrier after glucuronidation and certain drugs may be subject to direct glucuronidate in brain by the function of UGTs. The brain UGTs' isoforms, localization, induction, inhibition, and interaction with CYP and transporters are introduced in this review. The process of drug glucuronidation and distribution in brain is summarized for five drugs. A deep insight into the process of drug metabolism and distribution in brain may provide a valuable reference for drug design for the central nervous system.
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This study was designed to investigate the inhibitory effects of sciadopitysin on the catalytic activities of human 12 kinds of UDP-glucuronosyltransferases (UGTs) in vitro. The risk of drug-drug interactions (DDI) is predicted by in vitro-in vivo extrapolation (IV-IVE). Methods A panel of recombinant human UGT isoforms and human liver microsome (HLM) as well as a series substrates including 4-methyl umbelliferone (4-MU), trifluoperazine (TFP) and N-3-carboxypropyl-4-hydroxy-1, 8-naphthalimide (NCHN) (UGT1A1 specific fluorescent probe substrates) were used to characterize the inhibitory effects of sciadopitysin on human UGTs in vitro. The half maximum inhibitory concentration (IC50) and the constant of inhibition kinetics (Ki) were obtained by nonlinear regression using GraphPad Prism 6.0 software. The potential risk of DDI induced by UGT1A1 was predicted based on in vitro parameters. The results demonstrated that sciadopitysin had strong inhibitory effects on UGT1A1, UGT1A3, UGT1A8 and UGT1A10, with the remaining activity being below 30% at a final concentration of 10 μmol·L-1. For UGT1A1, UGT1A3, UGT1A8 and UGT1A10, the IC50 was 0.20 μmol·L-1 to 1.34 μmol·L-1, the inhibition kinetic constant Ki was 0.07 μmol·L-1 to 2.12 μmol·L-1. The AUC ratio of UGT1A1 can be increased by 19% to 147% at the oral dose of 240 mg·d-1. The sciadopitysin competitively inhibited the formation of 4-MU-O-glucuronide by UGT1A1, UGT1A3, UGT1A8, and UGT1A10. At the same time, the inhibition of NCHN-O-glucuronidation by UGT1A1 was consistent with the competitive inhibition. The strong inhibition of sciadopitysin on UGT1A1 led to reduction of the metabolism of UGT1A1 substrates, and increased the risk of DDI. When co-administrated with other drugs, special attentions should be given to the DDI from inhibition of drug metabolism enzymes to prevent serious clinical consequences.
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Glycyrrhizin is a major bioactive component of liquorice, which exerts multiple biochemical and pharmacological activities and is frequently used in combination with other drugs in the clinic. Mycophenolate mofetil (MMF), an immunosuppressant widely used in transplant patients, is metabolized by UDP-glucuronyltransferases (UGTs). Although significant evidence supports that glycyrrhizin could interact with the cytochrome P450s (CYPs), few studies have addressed its effects on UGTs. The present study aimed at investigating the regulatory effects of diammonium glycyrrhizinate (GLN) on UGTs in vitro and in vivo. We found that long-term administration of GLN in rats induced overall metabolism of MMF, which might be due to the induction of UGT1A protein expression. Hepatic UGT1A activity and UGT1A mRNA and protein expression were significantly increased in GLN-treated rats. UGT1A expression levels were also increased in the intestine, contradicting with the observed decrease in intestinal UGT1A activities. This phenomenon may be attributed to different concentrations of glycyrrhetinic acid (GA) in liver and intestine and the inhibitory effects of GA on UGT1A activity. In conclusion, our study revealed that GLN had multiple effects on the expression and activities of UGT1A isoforms, providing a basis for a better understanding of interactions between GLN and other drugs.
Subject(s)
Animals , Male , Rats , Drugs, Chinese Herbal , Chemistry , Pharmacology , Glucuronosyltransferase , Chemistry , Metabolism , Glycyrrhizic Acid , Chemistry , Pharmacology , Herb-Drug Interactions , Intestines , Chemistry , Kinetics , Liver , Chemistry , Rats, Sprague-DawleyABSTRACT
Objective To analyze the relationship between UDP-glucuronosyltransferase 1A1 (UGT1A1)gene polymorphism and delayed diarrhea caused by FOLFIRI treatment.Methods Two hundred and one blood samples were taken from patients with metastatic digestive tract tumor before chemotherapy by FOLFIRI and then the UGT1A1 * 28 genetic polymorphism was performed.All the cases treated with FOLFIRI were chosen to be observed and recorded by situation of the delayed diarrhea during chemotherapy,and to analyze the relationship between UGT1A1 * 28 genetic polymorphism and grade 3 and 4 delayed diarrhea.Results The distributions of the genotypes in 201 metastatic digestive tract tumor patients were as follows:UGT1A1 * 28 wild-type genotype TA6/6 (155,77.11％),heterozygous genotype TA6/7 together with homozygous genotype TA7/7 (46,22.89％).In the 201 cases,the incidences of grade 1 and 2 delayed diarrhea in the patients carrying wild-type genotype and mutant type were respectively 45.16％ (70/155),39.13％ (18/46).The incidences of grade 3 and 4 delayed diarrhea were respectively 9.68％ (15/155),19.57％ (9/46),with no statistical difference (x2 =3.318,P =0.190).Conclusion The UGT1A1 * 28 polymorphism TA6/7 or TA7/7 can not increase the risk of grade 3 or more severe delayed diarrhea for the patients with metastatic digestive tract tumor after receiving FOLFIRI treatment.
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OBJECTIVE: To establish a method to determine the genotypes of the three SNPs(-31T/C, -133C/T and -140T/C) of uridinediphosphateglucuronosyltransferase 1A3(UGT1A3)and to preliminarily analyze the genetic frequencies of different genotypes among healthy Chinese population. METHODS: The genotypes of the three SNPs(-31T/C, -133C/T and -140T/C) of 123 healthy Chinese subjects(89 males, 34 females) were screened by two-step allele specific amplification(two-step ASA) method. Firstly, a pair of primers of the first exon for the amplification of the genomic DNA were designed. And then two parallel reaction tubes were set up for each site which included a forward primer whose last base of 3'end pair with wild type or mutant type and an identical reverse prime for the amplification of the target gene. The amplification Results were examined to differentiate the genotypes. The validity was verified by direct sequencing. RESULTS: Among the 123 subjects, the frequencies of -31T and -31C were 0.776 and 0.224, of -133C and -133T were 0.935 and 0.065, of -140T and -140C were 0.915 and 0.085, respectively. Based on the genotyping Results, there were 59 cases of UGT1A3*1/*1, 1 case of UGT1A3*2/*2, 17 cases of UGT1A3*1/*2, 12 cases of UGT1A3*1/*4, and 1 case of UGT1A3*4/*4. CONCLUSION: There are genetic polymorphisms of UGT1A3 in healthy Chinese population and the mutation frequency is remarkable. The gene detection method established in this study is verified to be sensitive and specific.
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Objective To investigate the role of UDP-glucuronosyltransferase 1A (UGT1A),nuclear factor erythroid-2-related factor 2 (Nrf2) and kelch-like ECH-associated protein 1 ( Keapl ) in the tumorigenesis of colonic carcinoma.Methods The expressions of UGT1 A,Nrf2 and Keapl were detected in normal colonic mucosa(24 cases),adenoma tissue (30 cases) and adenocarcinoma tissue (77 cases) by immunohistochemistry,and the relationship between their expressions and the clinical pathological characteristics was analyzed.Results The positive rates of UGT1 A in normal colonic mucosa,adenoma and adenocarcinoma tissue were 83.3％ ( 20/24),80.0％ ( 24/30 ) and 53.2％ ( 41/77 ),respectively.The positive rate of UGT1A in adenocarcinoma was lower than those in colonic mucosa and adenoma ( all P ＜0.05 ).On the contrary,the positive rates of Nrf2 in adenoma [70.0％ (21/30) ] and adenocarcinoma tissue [ 87.0％ (67/77) ] were higher than that in normal colonic tissue [ 41.7％ (10/24),all P =0.000 ].The positive rates of Keapl in normal colonic mucosa,adenoma and adenocarcinoma tissue were 54.2％ ( 13/24),70.0％ (21/30) and 61.0％ (47/77),respectively ( normal colonic tissue vs adenocarcinoma tissue,P =0.040 ; adenoma vs adenocarcinoma,P =0.002 ).There was no correlation between the expression of UGT1 A,Nrf2 and the clinicopathologic features of colon carcinoma,while the differences of Keapl positive rates in the various degrees of tumor differentiation [ moderately-well differentiated vs poorly differentiated:70.0％ (35/50) vs 44.4％ (12/27) ] and invasion [T1-T2 vs T3-T4:78.8％ (26/33) vs 47.7％ (21/44) ]were statistically significant (all P ＜ 0.05 ).Conclusion The decreased expression of UGT1A and the dysregulation of Nrf2/Keapl system may play a role in colonic tumorigenesis.
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Patients with co-existing hereditary spherocytosis (HS) and UDP-glucuronosyltransferase 1A1 (UGT1A1) deficiency as Gilbert's syndrome (GS) have been reported, and previous studies have demonstrated an increased risk for developing gallstones in patients with co-inheritance of GS and HS. We experienced an interesting case of HS showing persistent jaundice after splenectomy, and upon further evaluation, the 25-year-old female patient was found to have HS combined with UGT1A1 deficiency. Sequence analysis of the UGT1A1 gene revealed that she was a compound heterozygote with p.[G71R; Y486D] + [Y486D] mutations, which suggests Crigler-Najjar syndrome type II rather than GS. Careful evaluation of inappropriately elevated bilirubin level compared with the degree of hemolysis is important, reflecting the therapeutic implication of splenectomy and cholecystectomy.
Subject(s)
Adult , Female , Humans , Crigler-Najjar Syndrome/genetics , Glucuronosyltransferase/deficiency , Heterozygote , Homozygote , Jaundice/etiology , Mutation, Missense/genetics , Point Mutation/genetics , Spherocytosis, Hereditary/complications , Splenectomy/adverse effectsABSTRACT
Objective To investigate the preventive effects of epigallocatechin gallate (EGCG) on growth and metastases of orthotropic colonic cancer. Methods Forty BALB/C male nude mice were prepared for model of colonic cancer and then divided into control group and low-, medium- and high-dose of EGCG groups with 10 each. Except control group, the mice in other three groups were treated with 5, 10 and 20 mg·kg~(-1)·d~(-1) of EGCG. The effect of EGCG on growth and metastases of colonic cancer was observed. The histopathologic changes of liver and lung were observed with HE, and protein expression of NF-E2-related factor 2 (Nrf2) in cancerous tissue was detected by immunohistochemistry. RT-PCR was used to examine mRNA levels of Nrf2, UDP-glucuronosyhrans-ferase (UGT)1A, UGT1A8 and UGT1A10. Results In comparison with control group [(564±130) mg], the average weight of the tumor in low-, medium- and high-dose groups was (152±63) mg, (76±42) mg and (18±10)mg, respectively, with tumor inhibitory rate of 73.0%, 86.5% and 96.8%, respectively (all P value<0.05). There was a positive correlation between tumor inhibitory effect and dosage of EGCG (P<0.05). The protein expression of Nrf2 and the mRNA levels of Nrf2, UGT1A, UGTIA8 and UGTIA10 in three EGCG treated groups were increased significantly compared with control group (P<0.05), and there was a phenomenon of nuclear transcription of Nrf2. Conclusions EGCG can prevent local growth and metastases of orthotopic colonic cancer in a dose-dependent manner in nude mice. The inhibitory effect may be caused by inducing the expressions of Nrf2, UGT1A, UGT1A8 and UGT1A10 genes.
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Gilbert's syndrome is a congenital,nonhemolytic,unconjugated hyperbilirubinemia.The intermittent mild jaundice is its clinical characteristic.The pathogenesis of the disease is the gene mutation of the isoenzyme which encoding the UDP-glucuronosyltransferase (UGT1A1).The gene mutation can affect glucuronic acidation of drugs.Therapeutic dose can cause unexpected toxicity.It is very important to detect the gene mutation of UGT1A1 for diagnosis,treatment and genetic counseling of Gilbert's syndrome.
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Crigler-Najjar syndrome is a rare inherited disease associated with unconjugated hyperbilirubinemia. It is inherited via an autosomal recessive pattern and is caused by mutation in one of the five exons of the bilirubin uridine-diphosphoglucuronate glucuronosyltransferase (UGT1A1) gene. The synthesis of inactive isoforms of bilirubin uridine-diphosphoglucuronate glucuronosyltransferase (B-UGT) results in unconjugated hyperbilirubinemia. A 13-year-old boy with jaundice for 4 months was admitted to our hospital. He had unconjugated hyperbilirubinemia with no evidence of infection, hemolysis, or structural abnormalities on abdominal ultrasonography or 99mTc-DISIDA scan. The authors identified a missense mutation of Tyr486Asp in the fifth exon of the UGT1A1 gene and diagnosed the patient with Crigler-Najjar syndrome type II. This is the first reported case of Crigler-Najjar syndrome in a Korean child, and it is also the first reported case of a genetic mutation leading to Crigler-Najjar syndrome in Korea.
Subject(s)
Adolescent , Child , Humans , Bilirubin , Crigler-Najjar Syndrome , Exons , Glucuronosyltransferase , Hemolysis , Hyperbilirubinemia , Jaundice , Mutation, Missense , Protein Isoforms , Technetium Tc 99m DisofeninABSTRACT
Crigler-Najjar syndrome is a rare inherited disease associated with unconjugated hyperbilirubinemia. It is inherited via an autosomal recessive pattern and is caused by mutation in one of the five exons of the bilirubin uridine-diphosphoglucuronate glucuronosyltransferase (UGT1A1) gene. The synthesis of inactive isoforms of bilirubin uridine-diphosphoglucuronate glucuronosyltransferase (B-UGT) results in unconjugated hyperbilirubinemia. A 13-year-old boy with jaundice for 4 months was admitted to our hospital. He had unconjugated hyperbilirubinemia with no evidence of infection, hemolysis, or structural abnormalities on abdominal ultrasonography or 99mTc-DISIDA scan. The authors identified a missense mutation of Tyr486Asp in the fifth exon of the UGT1A1 gene and diagnosed the patient with Crigler-Najjar syndrome type II. This is the first reported case of Crigler-Najjar syndrome in a Korean child, and it is also the first reported case of a genetic mutation leading to Crigler-Najjar syndrome in Korea.
Subject(s)
Adolescent , Child , Humans , Bilirubin , Crigler-Najjar Syndrome , Exons , Glucuronosyltransferase , Hemolysis , Hyperbilirubinemia , Jaundice , Mutation, Missense , Protein Isoforms , Technetium Tc 99m DisofeninABSTRACT
PURPOSE: The incidence of neonatal hyperbilirubinemia is twice as high in East Asians as in Caucasians. However, its metabolic basis has not been clearly explained. The UDP-glucuronosyltransferase gene(UGT1A1) mutation was found to be a risk factor of neonatal hyperbilirubinemia. We studied whether neonatal hyperbilirubinemia is associated with the 1828G>A(rs 10929303) polymorphism of the UGT1A1 gene, which encodes for a key enzyme of bilirubin metabolism. METHODS: The genomic DNA was isolated from 80 Korean full term neonates who had greater than a 12 mg/dL level of serum bilirubin with no obvious cause, and the genomic DNA was also isolated from 164 Korean neonates of the control population. We studied a single nucleotide polymorphism (SNP) of 1828G>A in the untranslated region of the UGT1A1 gene by direct sequencing. RESULTS: Three of the 80 neonates with a serum bilirubin level above 12 mg/dL had homozygous mutations and 10 of the 80 neonates with a serum bilirubin level above 12 mg/dL had heterozygous mutations. Thirteen of the 164 neonates of the control group had homozygous mutations and 16 neonates of the control group had heterozygous mutations. The allele frequency of 1828G>A polymorphism of UGT1A1 in the hyperbilirubinemia group was 10.0 percent, which was not significantly different from the allele frequency of 12.8 percent in the control group. CONCLUSION: In this study, the 1828G>A polymorphism of the UGT1A1 gene was detected in the Korean neonates with neonatal hyperbilirubinemia. Our results indicated that this SNP is not associated with the prevalence of hyperbilirubinemia in Koreans.
Subject(s)
Humans , Infant, Newborn , Asian People , Bilirubin , DNA , Gene Frequency , Hyperbilirubinemia , Hyperbilirubinemia, Neonatal , Incidence , Metabolism , Polymorphism, Single Nucleotide , Prevalence , Risk Factors , Untranslated RegionsABSTRACT
PURPOSE: The incidence of neonatal hyperbilirubinemia is twice as high in Eastern Asians as in Caucasians. Although it has not been clearly defined, the UDP-glucuronosyltransferase gene (UGT1A1) mutation was found to be a risk factor of neonatal hyperbilirubinemia. This study is to find an association of 1956G>C polymorphism of the UGT1A1 gene, which encodes for a key enzyme of bilirubin metabolism and neonatal hyperbilirubinemia in Korean infants. METHODS: The genomic DNA was isolated from 80 Korean full term neonates whose serum bilirubin greater than 12 mg/dL with no obvious cause. The genomic DNA was also isolated from 164 Korean neonates of the control population. We studied a single nucleotide polymorphism (SNP) of 1956G>C in the untranslated region of the UGT1A1 gene by direct sequencing. RESULTS: Three of the 80 neonates with a serum bilirubin level above 12 mg/dL had homozygous mutation and 10 of the neonates with a serum bilirubin level above 12 mg/dL had heterozygous mutation. Thirteen of the 164 neonates of the control group had homozygous mutation and 16 neonates of the control group had heterozygous mutation. The allele frequency of 1956G>C polymorphism of UGT1A1 in the hyperbilirubinemia group was 10.0 percent, which was not significantly different from the allelic frequency of 12.8 percent in the control group. CONCLUSIONS: In this study, the 1956G>C polymorphism of the UGT1A1 gene was detected in the Korean neonates with neonatal hyperbilirubinemia. Our results indicated that this SNP is not associated with the prevalence of hyperbilirubinemia in Korean.
Subject(s)
Humans , Infant , Infant, Newborn , Asian People , Bilirubin , DNA , Gene Frequency , Hyperbilirubinemia , Hyperbilirubinemia, Neonatal , Incidence , Metabolism , Polymorphism, Single Nucleotide , Prevalence , Risk Factors , Untranslated RegionsABSTRACT
PURPOSE: The incidence of neonatal hyperbilirubinemia is twice as high in East Asians as in whites and its metabolic basis has not been clearly explained. Recently, UDP-glucuronosyltransferase gene (UGT1A1) mutation was found to be a risk factor of neonatal hyperbilirubinemia in Japanese and Taiwanese Chinese. We studied whether neonatal hyperbilirubinemia is associated with mutation of UGT1A1, which is a key enzyme of bilirubin catabolism, in Korean. METHODS: The genomic DNA was isolated from 45 Korean full term neonates who had hyperbilirubinemia(serum bilirubin >12 mg/dL) with no obvious causes, and the 64 Korean neonates of the control population. We detected a missense mutation of Gly71Arg of UGT1A1 gene by using allele-specific polymerase chain reaction. Polymorphism was confirmed by direct sequencing. RESULTS: Two of the 45 neonates with serum bilirubin above 12 mg/dL had homozygous mutation and 16 neonates had heterozygous mutation. Two of the 31 neonates with serum bilirubin above 15 mg/dL had homozygous mutation and 13 neonates had heterozygous mutation. Thirteen of the control group had heterozygous mutation and homozygous mutation was not found. Allele frequency of Gly71Arg mutation in hyperbilirubinemia group was 0.22, which was significantly higher than 0.11 in the control group(P<0.0144). CONCLUSION: The missense mutation causing Gly71Arg of UGT1A1 was detected in the Korean neonatal hyperbilirubinemia. The high frequency of this missense mutation may be attributed to the high prevalence of hyperbilirubinemia in the Korean.
Subject(s)
Humans , Infant, Newborn , Asian People , Bilirubin , DNA , Gene Frequency , Hyperbilirubinemia , Hyperbilirubinemia, Neonatal , Incidence , Korea , Metabolism , Mutation, Missense , Polymerase Chain Reaction , Prevalence , Risk FactorsABSTRACT
BACKGROUNDS/AIMS: Hepatic glucuronidating activity, essential for efficient biliary excretion of bilirubin, is reduced to about 30 percent of normal in patients with Gilbert's syndrome. Patients with Gilbert's syndrome have an additional TA insertion in the A(TA)TAA of UDP-glucuronosyltransferase 1 (UGT-1A1) promoter gene. This results in reduced frequency and accuracy of transcription initiation and enzyme activity. The frequency and location of the mutation vary according to races. This study was done to determine the UGT-1A1 promoter gene mutation in Korean cases of Gilbert's syndrome. METHODS: Promoter regions of the gene for bilirubin UGT-1A1 in twelve patients with Gilbert's syndrome and twenty healthy subjects (controls) were sequenced. RESULTS: 1) Among twelve Gilbert's syndrome five patients were homozygous for A(TA)6/6TAA, two were homozygous for A(TA)7/7TAA, and the other five were heterozygous for A(TA)6/7TAA. The prevalence of A(TA)TAA mutation was 58.3 percent. 2) Among twenty healthy subjects seventeen were homozygous for A(TA)6/6TAA, one was homozygous for A(TA)7/7TAA, and two were heterozygous for A(TA)6/7TAA. The prevalence of A(TA)TAA mutation was 15 percent. 3) The prevalence of A(TA)TAA mutation in Gilbert's syndrome patients was significantly higher than in the controls (p=0.018). CONCLUSION: Although the prevalence of A(TA)TAA mutation in Korean patients with Gilbert's syndrome is significantly higher than in the controls, the mutations of the promoter region of UGT-1A1 gene appear not to be the main or sole cause in Gilbert's syndrome in Korea since the prevalence of A(TA)TAA mutation is not so high. Further studies to determine the relationship between other UGT-1A1 gene mutation and Gilbert's syndrome in Korea are needed.
Subject(s)
Adult , Female , Humans , Male , English Abstract , Gilbert Disease/enzymology , Glucuronosyltransferase/genetics , Korea , Mutation , Polymorphism, Genetic , Promoter Regions, Genetic/geneticsABSTRACT
Objective To analyze tissue-specific expression and polymorphic regulation of the UDP - glucuronosyltransferase (UGT) 1A gene in human tissue. Methods Forty colorectal cancer tissue. 20 normal colorectal tissue and 10 normal liver tissue were studied. UGT 1A transcriptions were investigated by exon-1 specific RT-PCR. UGT 1A proteins were studied using Western blotting analysis. Meanwhile catalytic activity of microsomes was evaluated using N-hydroxy-PhiP. Results (1) UGT 1A mRNA expressions were found to be significantly down-regulated in colorectal cancer tissue as compared with the surrounding normal tissues(P
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In this study, we investigated the effect of organosulfur compounds including, diallyl sulfide (DAS), garlic extract, and dially disulfide (DADS) on inducible expression of UDP-glucuronosyltransferase (UGT1) and thyroid hormone level in 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-treated rats. We measured UGT1 gene expression in rat liver and lung tissues after treatments. We found that a correlation was found to exist between UGT1 gene expression and active T-4 concentrations. The total concentration of plasma T-4 decreased in TCDD-alone treated male and female rats compared to control animals (TCDD-alone < control). Plasma T-4 concentration in TCDD + DAS, TCDD + garlic extract and TCDD + DADS treated groups were moderately higher than in TCDD alone animals, but lower than control animals. TCDD + DAS, TCDD + garlic extract and TCDD + DADS moderately increased T-4 glucuronidation and moderately reduced total T-4. The nonthyroidal nature of thyroid hormone reduction observed in this study extends the evidence for microsomal enzyme inducers as indirect thyroid tumor promoters in rats. Furthermore, the results of present study suggest protective effects of DAS, garlic extract, or DADS on TCDD-induced changes.
Subject(s)
Animals , Female , Humans , Male , Rats , Carcinogens , Garlic , Gene Expression , Liver , Lung , Plasma , Polychlorinated Dibenzodioxins , Thyroid GlandABSTRACT
We have investigated the effect of cholestasis on the hepatic thiosulfate sulfurtransferase (rhodanese) and UDP-glucuronosyltransferase (UDP-GT) activities in rats. Rhodanese activities in the liver cytosol, mitochondria and microsomal fractions as well as in the rat serum, and UDP-GT activity in the microsome have been investigated for a period of 42 days after common bile duct (CBD) ligation. The cytosolic rhodanese activity showed a significant decrease between the first through the 42nd day, and the mitochondrial activity showed a significant decrease between the 7th through the 42nd day after CBD ligation compared to the activities from the sham operated control, respectively. In the case of microsomal preparation, both rhodanese and UDP-GT also showed significant decrease in their activities after the ligation for the former enzyme between the 14th and the 42nd days, and for the latter enzyme between the third and 42nd days, respectively. On the other hand, the serum rhodanese activity increased markedly soon after the ligation, exhibiting the peak activity after 1 day of CBD ligation with about 4.6-fold increment. The activity subsequently decreased gradually reaching to the control level at the 42nd day post-ligation. Enzyme kinetic parameters of hepatic rhodanese and UDP-GT were analyzed using sodium thiosulfate and p-nitrophenol as substrates, respectively, with the preparations from the 28th day post-ligation. The results indicated that although the K-m values of these enzymes were about the same as the sham-operated control, the V-max values of the both enzymes decreased significantly. These results, therefore, suggest that the biosynthesis of rhodanese and UDP-GT have been reduced in response to cholestasis, and that the elevation of rhodanese activity in the serum is most likely due to leakage from the liver subsequent to CBD ligation.