• 한국임상약학회지
• /
• 제16권2호
• /
• pp.155-164
• /
• 2006

Great inter-variability in drug response and adverse drug reactions is related to inter-variability of drug bioavailability, drug interaction and patient's disease and physyological state that cause change in absorption, distribution, metabolism and excretion of drugs. However, these alone do not sufficiently predict and explain inter-variability in drug response. In recent studies, it is reported that inter-variability in drug response and adverse drug reactions may largely resulted from genetically determined differences in drug absoption, distribution, metabolism and drug target proteins. Especially, the major human drug-metabolizing enzymes such as CYP450, N-acetyl tranferase, thiopurine S-methyl transferase, glutathione S-transferase are identified as the major gene variants that cause inter-individual variability in drug's response and adverse drug reactions. These variations may have most significant implications for those drugs that have narrow therapeutic index and serious adverse drug reactions. Therefore, the genetic variation such as polymorphisms in drug metabolizing enzymes can affect the response of individuals to drugs that are used in the treatment of depression, psychosis, cancer, cardiovascular disorders, ulcer and gastrointestinal disorders, pain and epilepsy, among others. This review describes the pharmacogenomics of the drug metabolizing enzymes associated with the drug response and its clinical applications.

• Toxicological Research
• /
• 제17권
• /
• pp.299-304
• /
• 2001

Xenobiotics and their reactive intermediates bind to cellular macromolecules and/or generate oxidative stress. which provoke deleterious effects on the cell function. Induction of xenobiotic-biotrans-forming enzymes and antioxidant molecules is an important defense mechanism against such insults. A group of genes involved in the defense mechanism. e.g. genes encoding glutathione S-transferases. NAD(P)H: quinone oxidoreductase, UDP-glucuronosyltransferase (UDP-GT) and ${\gamma}$-glutamylcysteine synthetase (GGCS). have a common regulatory sequence, Antioxidant or Electrophile Responsive Element (ARE/EpRE). Recently. Nrf2. discovered as a homologue of erythroid transcription factor p45 NF-E2, was shown to bind ARE/EpRE and induce the expression of these defense genes. Mice that lack Nrf2 show low basal levels of expression and/or impaired induction of these genes. which makes the animals highly sensitive to xenobiotic toxicity. Indeed. we show here that nrf2-deficient mice had a higher mortality than did the wild-type mice when exposed to acetaminophen (APAP). Detailed analyses of APAP hepatotoxicity in the nrf2 knockout mice indicate that a large amount of reactive APAP metabolites was generated in the livers due to the impaired basal expression of two detoxifying enzyme genes, UDP-GT (Ugt1a6) and GGCS. while the cytochrome P450 content was unchanged. Thus. the studies using the nrf2 knockout mice clearly demonstrate significance of the expression of Nrf2-regulated enzymes in protection against xenobiotic toxicity.

• Biomolecules & Therapeutics
• /
• 제31권1호
• /
• pp.82-88
• /
• 2023

Genomic analysis indicated that the genome of Drosophila melanogaster contains more than 80 cytochrome P450 genes. To date, the enzymatic activity of these P450s has not been extensively studied. Here, the biochemical properties of CYP6A8 were characterized. CYP6A8 was cloned into the pCW vector, and its recombinant enzyme was expressed in Escherichia coli and purified using Ni²⁺-nitrilotriacetate affinity chromatography. Its expression level was approximately 130 nmol per liter of culture. Purified CYP6A8 exhibited a low-spin state in the absolute spectra of the ferric forms. Binding titration analysis indicated that lauric acid and capric acid produced type I spectral changes, with K_d values 28 ± 4 and 144 ± 20 µM, respectively. Ultra-performance liquid chromatography-mass spectrometry analysis showed that the oxidation reaction of lauric acid produced (ω-1)-hydroxylated lauric acid as a major product and ω-hydroxy-lauric acid as a minor product. Steady-state kinetic analysis of lauric acid hydroxylation yielded a k_cat value of 0.038 ± 0.002 min^-1 and a K_m value of 10 ± 2 µM. In addition, capric acid hydroxylation of CYP6A8 yielded kinetic parameters with a k_cat value of 0.135 ± 0.007 min^-1 and a K_m value of 21 ± 4 µM. Because of the importance of various lipids as carbon sources, the metabolic analysis of fatty acids using CYP6A8 in this study can provide an understanding of the biochemical roles of P450 enzymes in many insects, including Drosophila melanogaster.

• 한국식품영양과학회지
• /
• 제33권6호
• /
• pp.965-972
• /
• 2004

홍국이 bromobenzene에 의한 간 손상에 어떠한 영향을 미치는지를 알아보기 위하여 흰쥐 에 2% 및 4% 홍국 첨가식이로 1개월 간 성장시킨 다음 체중 1 kg당 400 mg의 bromobenzene을 1일 1회 복강으로 3회 투여한 다음, 24시간 후에 처치하여 다음과 같은 결과를 얻었다. 2% 및 4% 홍국 첨가식이로 성장시킨 흰쥐에 있어서 체중증가율은 표준식이군과 별다른 차이를 볼 수 없었으며 간 기능 및 병리조직검사에서도 홍국 섭취로 인한 간 조직의 병태생리적 변화가 관찰되지 않았다. 이러한 실험동물에 bromobenzene을 투여 시 간 손상 정도가 2% 홍국 첨가식이군에서 가장 경미하게 나타났다. 2% 홍국 첨가식이군에서 bromobenzene에 의한 간손상이 경미하게 나타난 원인을 구명하고자 간 손상 실험모델에bromobenaene을 재투여시, 간 조직 중 cytochrome P-450 dependant aniline hydroxylase 활성은 대조군에 비하여 2% 홍국 첨가식이군에서는 유의한 증가(p<0.01)를 보였으나 표준식이군 및 4% 홍국 첨가식이군은 오히려 감소하였다. 그리고 대조군에 대한 간 조직 glutathione 함량 감소율에 있어서는 2% 홍국 첨가식이군에서 표준식이군 및 4% 홍국 첨가식이군보다 높게 나타났다. 그러나 간 조직의 glutathione S-transferase 활성은 3군간에 별다른 차이를 볼 수 없었으나 반응속도적 측면에서는 2% 홍국 첨가식이군에서 표준식이군 및 4% 홍국 첨가식이군보다 V$_{max}$치가 높게 나타났다. 한편 bromobenzene 투여에 의한 간 조직의 cytochrome P-450 dependant aniline hydroxylase 증가율은 2% 홍국 첨가식이군에서 표준식이군 및 4% 홍국 첨가식이군보다 낮게 나타났으며, xanthine oxidase 활성은 3군간에 별다른 차이를 볼 수 없었다. 특히 대조군 및 bromobenzene 투여군 모두superoxidase dismutase, catalase, glutathione peroxidase 활성은 2% 홍국 첨가식이군에서 표준식이군 및 4% 홍국 첨가식이군보다 높게 나타났다. 이상 실험결과를 종합해 볼 때, 2% 홍국 첨가식이군에서 bromobenzene에 의한 간 손상이 경미하게 나타났으며, 이는 2% 흥국 첨가식이의 섭취로 인한 bromobenzene 대사 및 유해산소 해독의 촉진에 기인되기 때문일 것으로 생각된다.다.

• Biomolecules & Therapeutics
• /
• 제22권2호
• /
• pp.149-154
• /
• 2014

Effects of diallyl sulfide (DAS) on thioacetamide-induced hepatotoxicity and immunotoxicity were investigated. When male Sprague-Dawley rats were treated orally with 100, 200 and 400 mg/kg of DAS in corn oil for three consecutive days, the activity of cytochrome P450 (CYP) 2E1-selective p-nitrophenol hydroxylase was dose-dependently suppressed. In addition, the activities of CYP 2B-selective benzyloxyresorufin O-debenzylase and pentoxyresorufin O-depentylase were significantly induced by the treatment with DAS. Western immunoblotting analyses also indicated the suppression of CYP 2E1 protein and/or the induction of CYP 2B protein by DAS. To investigate a possible role of metabolic activation by CYP enzymes in thioacetamide-induced hepatotoxicity, rats were pre-treated with 400 mg/kg of DAS for 3 days, followed by a single intraperitoneal treatment with 100 and 200 mg/kg of thioacetamide in saline for 24 hr. The activities of serum alanine aminotransferase and aspartate aminotransferase significantly elevated by thioacetamide were protected in DAS-pretreated animals. Likewise, the suppressed antibody response to sheep erythrocytes by thioacetamide was protected by DAS pretreatment in female BALB/c mice. Taken together, our present results indicated that thioacetamide might be activated to its toxic metabolite(s) by CYP 2E1, not by CYP 2B, in rats and mice.

• Applied Microscopy
• /
• 제36권4호
• /
• pp.291-297
• /
• 2006

주류의 섭취가 산업화학물질의 생체 내 독성유발에 어떠한 영향을 미치는지를 검토하기 위해 흰쥐를 이용하여 15%에탄올을 6주간 섭취시킨 후, cyclohexane(CH)을 2일 간격으로 4회 복강 투여하고 24시간 후 다음과 같은 결과를 얻었다. CH의 투여로 인해 정상군과 비교하여 간 무게와 헐청내 xanthine oxidase활성은 증가되었고, 간 내 glucose-6-phosphatase활성은 감소되었다. 그리고 CH 대사효소인 cytochrome P450 dependent aniline hydroxylase와 alcohol dehydrogenase의 활성은 CH투여 후 유의적으로 증가되었으며, 알코올 전처치 후 CH투여군이 가장 높은 활성을 보였다. 미세구조적으로도 알코올 섭취군과 CH투여군 모두에서 조면소포체로부터 활면소포체로의 전환이 일어났으며, 전 실험군 중 알코올 전처치 후 CH투여군이 가장 높은 전환율을 보였다. 이러한 결과들로 볼 때, 병변을 초래하지 않는 수준의 알코올의 섭취는 CH대사활성을 증대시키는 것으로 판단되었다.

• Journal of Ginseng Research
• /
• 제42권3호
• /
• pp.370-378
• /
• 2018

Background: Ginseng has been the subject of many experimental and clinical studies to uncover the diverse biological activities of its constituent compounds. It is a traditional medicine that has been used for its immunostimulatory, antithrombotic, antioxidative, anti-inflammatory, and anticancer effects. Ginseng may interact with concomitant medications and alter metabolism and/or drug transport, which may alter the known efficacy and safety of a drug; thus, the role of ginseng may be controversial when taken with other medications. Methods: We extensively assessed the effects of Korean Red Ginseng (KRG) in rats on the expression of enzymes responsible for drug metabolism [cytochrome p450 (CYP)] and transporters [multiple drug resistance (MDR) and organic anion transporter (OAT)] in vitro and on the pharmacokinetics of two probe drugs, midazolam and fexofenadine, after a 2-wk repeated administration of KRG at different doses. Results: The results showed that 30 mg/kg KRG significantly increased the expression level of CYP3A11 protein in the liver and 100 mg/kg KRG increased both the mRNA and protein expression of OAT1 in the kidney. Additionally, KRG significantly increased the mRNA and protein expression of OAT1, OAT3, and MDR1 in the liver. Although there were no significant changes in the metabolism of midazolam to its major metabolite, 1'-hydroxymidazolam, KRG significantly decreased the systemic exposure of fexofenadine in a dose-dependent manner. Conclusion: Because KRG is used as a health supplement, there is a risk of KRG overdose; thus, a clinical trial of high doses would be useful. The use of KRG in combination with P-glycoprotein substrate drugs should also be carefully monitored.

• 한국식품영양과학회지
• /
• 제28권1호
• /
• pp.212-217
• /
• 1999

The effects of nuruk and wheat bran on cholesterol level in serum and activities of free radical metabolizing enzymes were investigated in rats. The rats were fed a diet containing nuruk or wheat bran for one month. Body weight and food intake were measured. Animals were sacrificed after one month. The increased food efficiency ratio throughout whole growth period was observed in the rats fed with either nuruk containing Aspergillus terreus or wheat bran compared with control group on normal diet. In the rats fed with nuruk, hepatic GSH content, glutathione S transferase activity, hepatic cytochrome P 450 content, and aniline hydroxylase activities were generally increased. In the rats fed with nuruk containing other fungi except Aspergillus terreus, xanthine oxidase activity was decreased. The decreased cholesterol level in serum was observed in rats fed with nuruk prepared from Aspergillus terreus and wheat bran. LDL cholesterol level was decreased in rats fed with nuruk prepared with other fungi such as Penicillium sp. and Rhizopus sp. But HDL cholesterol level was increased in all groups fed with nuruk from any fungi and wheat bran. These results suggested that nuruk or wheat bran supplemented diet might exert their effect by decreasing cholesterol level in serum and amount of oxygen free radical level.

• 한국식품영양과학회:학술대회논문집
• /
• 한국식품영양과학회 2004년도 Annual Meeting and International Symposium
• /
• pp.65-70
• /
• 2004

Modulation of biotransformation enzymes is one mechanism by which a diet high in fruits and vegetable may influence cancer risk. Inhibition of cytochrome P450s (CYP) and concomitant induction of conjugating enzymes are hypothesized to reduce the impact of carcinogens in humans. Thus, exposure to types and amounts of phytochemicals may influence disease risk. Like other xenobiotics, many classes of phytochemicals are rapodly conjugated with glutathione, glucuronide, and sulfate moieties and excreted in urine and bile. In humans, circulating phytochemical levels very widely among individuals even in response to controlled dietary interventions. Polymorphisms in biotransformation enzymes, such as the glutathione S-transferases (GST), UDP-glucuronosyltransferases (UGT), and sulfotransferases (SULT), may ocntribute to the variability in phytochemical clearance and efficacy; polymorphic enzymes with lower enzyme activity prolong the half-lives of phytochmicals in vivo. Isothiocyanates (ITC) in cruciferous vegetables are catalyzed by the four major human GSTs: however reaction velocities of the enzymes differ greatly. In some observational studies of cancer, polymorphisms in the GSTMI and GSTTI genes that result in complete lack of GSTM1-1 protein, respectively, confer greater protection from cruciferous vegetable in individuals with these genotypes. Similarly, we have shown in a controlled dietary trial that levels of GST-alpha-induced by ITC-are higher in GSTMI-null individuals exposed to cruciferous vegetablse. The selectivity of glucuronosyl conjugation of flavonoids is dependent both on flavonoid structure as well as on the UGI isozyme involved in its conjuagtion. The effects of UGI polymorphisms on flavonoid clearnace have not been examind; but polymorphisms affect glucuronidation of several drugs. Given the strong interest in the chemopreventive effects of flavonoids, systematic evaluation of these polymorphic UGTs and flavonoid pharmacokinetics are warranted. Overall, these studies suggest that for phytochemicals that are metabolized by, and affect activity of, biotransformation enzymes, interactions between genetic polymorphisms in the enzymes and intake of the compounds should be considered in studies of cancer risk. Genetic polymorphisms in biotransformation enzymes may account in prat for individual variation in metabolism of a wide range of phytochemicals and their ultimate impact on health.

• Applied Biological Chemistry
• /
• 제39권1호
• /
• pp.77-83
• /
• 1996

이스라엘 잉어에 있어서 carbamate계 살충제 carbofuran의 독성에 미치는 phenobarbital sodium(PB) 또는 3-methylcholanthrene (3-MC)의 영향과 작용기작을 효소적 측면에서 구명할 목적으로 carbofuran과 PB나 3-MC를 이스라엘 잉어에 각 조합으로 처리하여 독성경감 효과를 조사하였고, 공시한 농약과 PB나 MC가 acetylcholinesterase(AChE), glutathione S-transferase(GST), UDP-glucuronosyltransferase(UDPGT) 및 cytochrome P-450-dependent monooxygenase(monooxygenase)의 효소활성에 미치는 영향을 조사하기 위하여 carbofuran과 PB나 3-MC를 각각 조합으로 처리한 후 경시적으로 이스라엘 잉어의 각 효소들의 상대활성도를 조사하였다. PB와 3-MC만 투여한 실험군에서 이스라엘 잉어의 생존수는 무처리군과 동일하였고 살충제만 처리한 실험군의 이스라엘 잉어 생존수는 처리농도가 증가하면서 감소되었으나, PB나 3-MC와 살충제를 조합처리한 실험군에서는 살충제만 처리한 실힘군에 비하여 매우 높은 생존율을 나타낸 것으로 보아 해독효과가 인정 되었다. 효소활성(in vivo)은 AChE의 경우 carbofuran 0.95 ppm만을 처리한 실험군에서는 24시간내내 각 조사시기마다 무처리군에 비해 40% 이상의 활성저해를 보였으나 carbofuran과 PB 및 3-MC를 조합처리한 실험군에서는 효소활성이 초기에 감소하다가 서서히 증가하여 24시간후에는 무처리군과 비슷한 수준을 나타냈고, GST의 경우 carbofuran만을 처리한 실험군에서는 초기에 약 20% 이상의 활성저해를 보였으나 carbofuran과 PB나 3-MC를 조합처리한 실험군에서는 약제처리 1시간 후 부터 무처리군에 비해 효소활성이 20% 이상 증가하였다. UDPGT와 monooxygenase의 효소활성은 carbofuran과 PB나 3-MC를 조합처리한 실험에서 처리 $6{\sim}12$시간 후에는 carbofuran 처리군에 비해 효소활성이 $4{\sim}8$배 이상 급격히 높아졌다. 이상의 결과에서 PB 및 3-MC처리가 이들 효소의 활성을 유도함으로써 carbofuran의 독성으로 부터 이스라엘 잉어를 보호 하는데 관여한 것으로 보인다.