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Yang G, Ge S, Singh R, Basu S, Shatzer K, Zen M, Liu J, Tu Y, Zhang C, Wei J, Shi J, Zhu L, Liu Z, Wang Y, Gao S, Hu M. Glucuronidation: driving factors and their impact on glucuronide disposition. Drug Metab Rev 2017; 49:105-138. [PMID: 28266877 DOI: 10.1080/03602532.2017.1293682] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Glucuronidation is a well-recognized phase II metabolic pathway for a variety of chemicals including drugs and endogenous substances. Although it is usually the secondary metabolic pathway for a compound preceded by phase I hydroxylation, glucuronidation alone could serve as the dominant metabolic pathway for many compounds, including some with high aqueous solubility. Glucuronidation involves the metabolism of parent compound by UDP-glucuronosyltransferases (UGTs) into hydrophilic and negatively charged glucuronides that cannot exit the cell without the aid of efflux transporters. Therefore, elimination of parent compound via glucuronidation in a metabolic active cell is controlled by two driving forces: the formation of glucuronides by UGT enzymes and the (polarized) excretion of these glucuronides by efflux transporters located on the cell surfaces in various drug disposition organs. Contrary to the common assumption that the glucuronides reaching the systemic circulation were destined for urinary excretion, recent evidences suggest that hepatocytes are capable of highly efficient biliary clearance of the gut-generated glucuronides. Furthermore, the biliary- and enteric-eliminated glucuronides participate into recycling schemes involving intestinal microbes, which often prolong their local and systemic exposure, albeit at low systemic concentrations. Taken together, these recent research advances indicate that although UGT determines the rate and extent of glucuronide generation, the efflux and uptake transporters determine the distribution of these glucuronides into blood and then to various organs for elimination. Recycling schemes impact the apparent plasma half-life of parent compounds and their glucuronides that reach intestinal lumen, in addition to prolonging their gut and colon exposure.
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Affiliation(s)
- Guangyi Yang
- a Department of Pharmacy , Institute of Wudang Herbal Medicine Research, Taihe Hospital, Hubei University of Medicine , Shiyan , Hubei , China.,b Hubei Provincial Technology and Research Center for Comprehensive Development of Medicinal Herbs, Hubei University of Medicine , Shiyan , Hubei , China
| | - Shufan Ge
- c Department of Pharmacological and Pharmaceutical Sciences , College of Pharmacy, University of Houston , Houston , TX , USA
| | - Rashim Singh
- c Department of Pharmacological and Pharmaceutical Sciences , College of Pharmacy, University of Houston , Houston , TX , USA
| | - Sumit Basu
- c Department of Pharmacological and Pharmaceutical Sciences , College of Pharmacy, University of Houston , Houston , TX , USA
| | - Katherine Shatzer
- c Department of Pharmacological and Pharmaceutical Sciences , College of Pharmacy, University of Houston , Houston , TX , USA
| | - Ming Zen
- d Department of Thoracic and Cardiomacrovascular Surgery , Taihe Hospital, Hubei University of Medicine , Shiyan , Hubei , China
| | - Jiong Liu
- e Department of Digestive Diseases Surgery , Taihe Hospital, Hubei University of Medicine , Shiyan , Hubei , China
| | - Yifan Tu
- c Department of Pharmacological and Pharmaceutical Sciences , College of Pharmacy, University of Houston , Houston , TX , USA
| | - Chenning Zhang
- a Department of Pharmacy , Institute of Wudang Herbal Medicine Research, Taihe Hospital, Hubei University of Medicine , Shiyan , Hubei , China
| | - Jinbao Wei
- a Department of Pharmacy , Institute of Wudang Herbal Medicine Research, Taihe Hospital, Hubei University of Medicine , Shiyan , Hubei , China
| | - Jian Shi
- f Department of Pharmacy , Institute of Translational Chinese Medicine, Guangzhou University of Chinese Medicine , Guangzhou , Guangdong , China
| | - Lijun Zhu
- f Department of Pharmacy , Institute of Translational Chinese Medicine, Guangzhou University of Chinese Medicine , Guangzhou , Guangdong , China
| | - Zhongqiu Liu
- f Department of Pharmacy , Institute of Translational Chinese Medicine, Guangzhou University of Chinese Medicine , Guangzhou , Guangdong , China
| | - Yuan Wang
- g Department of Pharmacy , College of Pharmacy, Hubei University of Medicine , Shiyan , Hubei , China
| | - Song Gao
- c Department of Pharmacological and Pharmaceutical Sciences , College of Pharmacy, University of Houston , Houston , TX , USA.,g Department of Pharmacy , College of Pharmacy, Hubei University of Medicine , Shiyan , Hubei , China
| | - Ming Hu
- c Department of Pharmacological and Pharmaceutical Sciences , College of Pharmacy, University of Houston , Houston , TX , USA.,g Department of Pharmacy , College of Pharmacy, Hubei University of Medicine , Shiyan , Hubei , China
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Sandwich-Cultured Hepatocytes as a Tool to Study Drug Disposition and Drug-Induced Liver Injury. J Pharm Sci 2016; 105:443-459. [PMID: 26869411 DOI: 10.1016/j.xphs.2015.11.008] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 11/06/2015] [Accepted: 11/09/2015] [Indexed: 12/21/2022]
Abstract
Sandwich-cultured hepatocytes (SCH) are metabolically competent and have proper localization of basolateral and canalicular transporters with functional bile networks. Therefore, this cellular model is a unique tool that can be used to estimate biliary excretion of compounds. SCH have been used widely to assess hepatobiliary disposition of endogenous and exogenous compounds and metabolites. Mechanistic modeling based on SCH data enables estimation of metabolic and transporter-mediated clearances, which can be used to construct physiologically based pharmacokinetic models for prediction of drug disposition and drug-drug interactions in humans. In addition to pharmacokinetic studies, SCH also have been used to study cytotoxicity and perturbation of biological processes by drugs and hepatically generated metabolites. Human SCH can provide mechanistic insights underlying clinical drug-induced liver injury (DILI). In addition, data generated in SCH can be integrated into systems pharmacology models to predict potential DILI in humans. In this review, applications of SCH in studying hepatobiliary drug disposition and bile acid-mediated DILI are discussed. An example is presented to show how data generated in the SCH model were used to establish a quantitative relationship between intracellular bile acids and cytotoxicity, and how this information was incorporated into a systems pharmacology model for DILI prediction.
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Quantification of drug transport function across the multiple resistance-associated protein 2 (Mrp2) in rat livers. Int J Mol Sci 2014; 16:135-47. [PMID: 25547484 PMCID: PMC4307239 DOI: 10.3390/ijms16010135] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 12/03/2014] [Indexed: 01/13/2023] Open
Abstract
To understand the transport function of drugs across the canalicular membrane of hepatocytes, it would be important to measure concentrations in hepatocytes and bile. However, these concentration gradients are rarely provided. The aim of the study is then to measure these concentrations and define parameters to quantify the canalicular transport of drugs through the multiple resistance associated-protein 2 (Mrp2) in entire rat livers. Besides drug bile excretion rates, we measured additional parameters to better define transport function across Mrp2: (1) Concentration gradients between hepatocyte and bile concentrations over time; and (2) a unique parameter (canalicular concentration ratio) that represents the slope of the non-linear regression curve between hepatocyte and bile concentrations. This information was obtained in isolated rat livers perfused with gadobenate dimeglumine (BOPTA) and mebrofenin (MEB), two hepatobiliary drugs used in clinical liver imaging. Interestingly, despite different transport characteristics including excretion rates into bile and hepatocyte clearance into bile, BOPTA and MEB have a similar canalicular concentration ratio. In contrast, the ratio was null when BOPTA was not excreted in bile in hepatocytes lacking Mrp2. The canalicular concentration ratio is more informative than bile excretion rates because it is independent of time, bile flows, and concentrations perfused in portal veins. It would be interesting to apply such information in human liver imaging where hepatobiliary compounds are increasingly investigated.
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Yang K, Brouwer KLR. Hepatocellular exposure of troglitazone metabolites in rat sandwich-cultured hepatocytes lacking Bcrp and Mrp2: interplay between formation and excretion. Drug Metab Dispos 2014; 42:1219-26. [PMID: 24799397 PMCID: PMC4053994 DOI: 10.1124/dmd.114.057190] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Accepted: 05/05/2014] [Indexed: 11/22/2022] Open
Abstract
Inhibition of bile acid transport by troglitazone (TGZ) and its major metabolite, TGZ sulfate (TS), may lead to hepatocellular accumulation of toxic bile acids; TS accumulation and hepatotoxicity may be associated with impaired TS biliary excretion. This study evaluated the impact of impaired transport of breast cancer resistance protein (Bcrp) and multidrug resistance-associated protein 2 (Mrp2) on the hepatobiliary disposition of generated metabolites, TS and TGZ glucuronide (TG). Sandwich-cultured hepatocytes (SCH) from Mrp2-deficient (TR(-)) rats in combination with Bcrp knockdown using RNA interference were employed. The biliary excretion index (BEI) of generated TS was not significantly altered by impaired Bcrp (20.9 to 21.1%) and/or Mrp2 function (24.4% and 17.5% in WT and TR(-) rat SCH, respectively). Thus, loss-of-function of Mrp2 and/or Bcrp do not appear to be risk factors for increased hepatocellular TS accumulation in rats, potentially because of a compensatory transporter(s) that excretes TS into bile. Further investigations revealed that the compensatory TS biliary transporter was not the bile salt export pump (Bsep) or P-glycoprotein (P-gp). Interestingly, TGZ sulfation was significantly decreased in TR(-) compared with WT rat SCH (total recovery: 2.8 versus 5.0% of TGZ dose), resulting in decreased hepatocellular TS accumulation, even though sulfotransferase activity in TR(-) rat hepatocyte S9 fraction was similar. Hepatocellular TG accumulation was significantly increased in TR(-) compared with WT rat SCH due to increased glucuronidation and negligible TG biliary excretion. These data emphasize that the interplay between metabolite formation and excretion determines hepatocellular exposure to generated metabolites such as TS and TG.
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Affiliation(s)
- Kyunghee Yang
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Kim L R Brouwer
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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