Species Differences in Tissue Distribution and Enzyme Activities of Arylacetamide Deacetylase in Human, Rat, and Mouse

Kobayashi, Yuki; Fukami, Tatsuki; Nakajima, Akinori; Watanabe, Akinobu; Nakajima, Miki; Yokoi, Tsuyoshi

doi:10.1124/dmd.111.043067

Cited by 67 publications

(65 citation statements)

References 25 publications

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“…Rat liver microsomes (RLM) were prepared according to our previous study (Kobayashi et al, 2012b). The protein concentrations were determined according to the method of Bradford (1976) using g-globulin as the standard.…”

Section: Methodsmentioning

confidence: 99%

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Carbamazepine-Induced Liver Injury Requires CYP3A-Mediated Metabolism and Glutathione Depletion in Rats

et al. 2015

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Carbamazepine (CBZ) is widely used as an antiepileptic agent and causes rare but severe liver injury in humans. It has been generally recognized that reactive metabolites formed via the metabolic activation reaction contribute to the onset of liver injuries by several drugs. However, the role of CBZ metabolism in the development of liver injury is not fully understood. In this study, we developed a novel rat model of CBZ-induced liver injury and attempted to elucidate the associated mechanisms by focusing on the metabolism of CBZ. The repeated administration of CBZ for 5 days in combination with L-buthionine sulfoximine (BSO), a glutathione (GSH) synthesis inhibitor, resulted in increases in the plasma alanine aminotransferase (ALT) levels and centrilobular necrosis in the liver that were observed in various degrees. The CBZ and 2-hydroxy-CBZ concentrations in the plasma after the last CBZ administration were lower in the rats with high plasma ALT levels compared with those with normal plasma ALT levels, showing the possibility that the further metabolism of CBZ and/ or 2-hydroxy-CBZ is associated with the liver injury. Although a single administration of CBZ did not affect the plasma ALT levels, even when cotreated with BSO, pretreatment with dexamethasone, a CYP3A inducer, increased the plasma ALT levels. In addition, the rats cotreated with troleandomycin or ketoconazole, CYP3A inhibitors, suppressed the increased plasma ALT levels. In conclusion, reactive metabolite(s) of CBZ produced by CYP3A under the GSH-depleted condition might be involved in the development of liver injury in rats.

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Section: Methodsmentioning

confidence: 99%

“…SDS-PAGE and immunoblot analysis were performed according to our previous study (Kobayashi et al, 2012b). RLM (10 mg) were separated on 7.5% polyacrylamide gels and electrotransferred onto a polyvinylidene difluoride membrane (Immobilon-P; Millipore, Billerica, MA).…”

Section: Methodsmentioning

confidence: 99%

Carbamazepine-Induced Liver Injury Requires CYP3A-Mediated Metabolism and Glutathione Depletion in Rats

et al. 2015

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“…6A). Such species differences are not surprising because it has been previously reported that there are species differences in substrate specificity among human, rat, and mouse AADAC (Kobayashi et al, 2012b).…”

Section: Discussionmentioning

confidence: 85%

Arylacetamide Deacetylase is Responsible for Activation of Prasugrel in Human and Dog

Kurokawa

Fukami

Yoshida

et al. 2015

Drug Metabolism and Disposition

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Prasugrel, a thienopyridine anti-platelet agent, is pharmacologically activated by hydrolysis and hydroxylation. It is efficiently hydrolyzed in the intestine after oral administration, and the enzyme responsible for the hydrolysis in humans was demonstrated to be carboxylesterase (CES)2. Prasugrel hydrolase activity is detected in dog intestines, where CES enzymes are absent; therefore, this prompted us to investigate the involvement of an enzyme(s) other than CES. Human arylacetamide deacetylase (AADAC) is highly expressed in the small intestine, catalyzing the hydrolysis of several clinical drugs containing small acyl moieties. In the present study, we investigated whether AADAC catalyzes prasugrel hydrolysis. Recombinant human AADAC was shown to catalyze prasugrel hydrolysis with a CL int value of 50.0 6 1.2 ml/min/mg protein with a similar K m value to human intestinal and liver microsomes, whereas the CL int values of human CES1 and CES2 were 4.6 6 0.1 and 6.6 6 0.3 ml/min/mg protein, respectively. Inhibition studies using various chemical inhibitors and the relative activity factor approach suggested that the contribution of AADAC to prasugrel hydrolysis in human intestine is comparable to that of CES2. In dog intestine, the expression of AADAC, but not CES1 and CES2, was confirmed by measuring the marker hydrolase activities of each human esterase. The similar K m values and inhibition profiles between recombinant dog AADAC and small intestinal microsomes suggest that AADAC is a major enzyme responsible for prasugrel hydrolysis in dog intestine. Collectively, we found that AADAC largely contributes to prasugrel hydrolysis in both human and dog intestine.

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“…The prasugrel, a thienopyridine prodrug, hydrolase activity by human CES2 was also inhibited at high concentrations, although data for its hydrolysis were not fitted to a single substrate inhibition equation (Williams et al, 2008). In our previous studies (Watanabe et al, 2009;Kobayashi et al, 2012), the flutamide hydrolase activity in HLM was fitted to the Michaelis-Menten equation, and the EadieHofstee plot was not obviously biphasic. Therefore, we mistakenly believed that AADAC was the major enzyme responsible for flutamide hydrolysis.…”

Section: Resultsmentioning

confidence: 93%

Contributions of Arylacetamide Deacetylase and Carboxylesterase 2 to Flutamide Hydrolysis in Human Liver

Kobayashi

Fukami²,

Shimizu³

et al. 2012

Drug Metab Dispos

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ABSTRACT:Flutamide, an antiandrogen drug, is widely used for the treatment of prostate cancer. The major metabolic pathways of flutamide are hydroxylation and hydrolysis. The hydrolyzed metabolite, 5-amino-2-nitrobenzotrifluoride (FLU-1), is further metabolized to N-hydroxy FLU-1, an assumed hepatotoxicant. Our previous study demonstrated that arylacetamide deacetylase (AADAC), one of the major serine esterases expressed in the human liver and gastrointestinal tract, catalyzes the flutamide hydrolysis. However, the enzyme kinetics in human tissue microsomes were not consistent with the kinetics by recombinant human AADAC. Thus, it seemed that AADAC is not the sole enzyme responsible for flutamide hydrolysis in human. In the present study, we found that recombinant carboxylesterase (CES) 2 could hydrolyze flutamide at low concentrations of flutamide. In the inhibition assay, the flutamide hydrolase activities at a flutamide concentration of 5 M in human liver and jejunum microsomes were strongly inhibited by a selective CES2 inhibitor, 10 M loperamide, with the residual activities of 22.9 ؎ 3.5 and 18.6 ؎ 0.7%, respectively. These results suggest that CES2 is also involved in the flutamide hydrolysis in human tissues. Using six individual human livers, the contributions of AADAC and CES2 to flutamide hydrolysis were estimated by using the relative activity factor. The relative contribution of CES2 was approximately 75 to 99% at the concentration of 5 M flutamide. In contrast, the relative contribution of AADAC increased in parallel with the concentration of flutamide. Thus, CES2, rather than AA-DAC, largely contributed to the flutamide hydrolysis in clinical therapeutics.

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Species Differences in Tissue Distribution and Enzyme Activities of Arylacetamide Deacetylase in Human, Rat, and Mouse

Cited by 67 publications

References 25 publications

Carbamazepine-Induced Liver Injury Requires CYP3A-Mediated Metabolism and Glutathione Depletion in Rats

Carbamazepine-Induced Liver Injury Requires CYP3A-Mediated Metabolism and Glutathione Depletion in Rats

Arylacetamide Deacetylase is Responsible for Activation of Prasugrel in Human and Dog

Contributions of Arylacetamide Deacetylase and Carboxylesterase 2 to Flutamide Hydrolysis in Human Liver

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