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Current Drug Metabolism 2019Common marmosets (Callithrix jacchus) are potentially useful nonhuman primate models for preclinical studies. Information for major drug-metabolizing cytochrome P450... (Review)
Review
BACKGROUND
Common marmosets (Callithrix jacchus) are potentially useful nonhuman primate models for preclinical studies. Information for major drug-metabolizing cytochrome P450 (P450) enzymes is now available that supports the use of this primate species as an animal model for drug development. Here, we collect and provide an overview of information on the activities of common marmoset hepatic and intestinal microsomes with respect to 28 typical human P450 probe oxidations.
RESULTS
Marmoset P450 2D6/8-dependent R-metoprolol O-demethylation activities in hepatic microsomes were significantly correlated with those of midazolam 1'- and 4-hydroxylations, testosterone 6β-hydroxylation, and progesterone 6β-hydroxylation, which are probe reactions for marmoset P450 3A4/5/90. In marmosets, the oxidation activities of hepatic microsomes and intestinal microsomes were roughly comparable for midazolam and terfenadine. Overall, multiple forms of marmoset P450 enzymes in livers and intestines had generally similar substrate recognition functionalities to those of human and/or cynomolgus monkey P450 enzymes.
CONCLUSION
The marmoset could be a model animal for humans with respect to the first-pass extraction of terfenadine and related substrates. These findings provide a foundation for understanding individual pharmacokinetic and toxicological results in nonhuman primates as preclinical models and will help to further support understanding of the molecular mechanisms of human P450 function.
Topics: Animals; Callithrix; Humans; Intestinal Mucosa; Liver; Microsomes; Models, Animal; Oxidation-Reduction; Pharmaceutical Preparations
PubMed: 30280664
DOI: 10.2174/1389200219666181003143312 -
Biological & Pharmaceutical Bulletin 2017Uridine 5'-diphosphate-glucuronosyltransferase (UGT) is expressed in the liver and extrahepatic tissues. One of the major metabolic pathways of β-estradiol (E2) is... (Comparative Study)
Comparative Study
Uridine 5'-diphosphate-glucuronosyltransferase (UGT) is expressed in the liver and extrahepatic tissues. One of the major metabolic pathways of β-estradiol (E2) is glucuronidation at the 17-hydroxy position by UGTs. This study was performed to determine E2 17-glucuronidation kinetics in human and rodent liver, small intestine, and kidney microsomes and to clarify the species and tissue differences. In the human liver and small intestine, Eadie-Hofstee plots exhibited biphasic kinetics, suggesting that E2 17-glucuronide (E17G) formation was catalyzed by more than two UGT isoforms in both tissues. The K values for E17G formation by the high-affinity enzymes in the human liver and small intestine were 1.79 and 1.12 µM, respectively, and corresponding values for the low-affinity enzymes were 3.72 and 11.36 µM, respectively. Meanwhile, E17G formation in the human kidney was fitted to the Hill equation (S=1.73 µM, n=1.63), implying that the UGT isoform catalyzing E17G formation in the kidney differed from that in the liver and small intestine. The maximum clearance for E17G formation in the human kidney was higher than the intrinsic clearance in the liver. E17G formation in the rat liver and kidney exhibited biphasic kinetics, whereas that in the small intestine was fitted to the Hill equation. In mice, all 3 tissues exhibited biphasic kinetics. In conclusion, we reported species and tissue differences in E2 17-glucuronidation, which occurred not only in the human liver but also in the extrahepatic tissues particularly the kidney.
Topics: Animals; Estradiol; Glucuronides; Humans; Intestine, Small; Kidney; Liver; Male; Mice, Inbred C57BL; Microsomes; Rats, Sprague-Dawley; Species Specificity
PubMed: 28966247
DOI: 10.1248/bpb.b17-00365 -
Chemical Research in Toxicology Jan 20162,5-Dimethoxy-N-benzylphenethylamines (NBOMes) are very potent 5-HT2AR agonists. Illicit use of these psychedelic compounds has emerged in recent years, and several...
2,5-Dimethoxy-N-benzylphenethylamines (NBOMes) are very potent 5-HT2AR agonists. Illicit use of these psychedelic compounds has emerged in recent years, and several fatalities have been linked to their recreational use. In its [(11)C]-labeled form, one NBOMe (25B-NBOMe) was recently developed as a PET-ligand for clinical investigations of 5HT2AR ([(11)C]Cimbi-36). Herein, we have identified the phase I and phase II metabolites of 25B-NBOMe in pigs as well as in humans. We find that the primary route of metabolism is 5'-demethylation, followed by conjugation to glucuronic acid. Carbon-11 labeling of 25B-NBOMe in three different positions followed by in vivo evaluation in pigs and humans corroborated these findings.
Topics: Animals; Hallucinogens; Humans; Microsomes, Liver; Molecular Structure; Phenethylamines; Positron-Emission Tomography; Swine
PubMed: 26669514
DOI: 10.1021/acs.chemrestox.5b00450 -
Effects of glycyrrhizin on the pharmacokinetics of paeoniflorin in rats and its potential mechanism.Pharmaceutical Biology Dec 2019Paeoniflorin is reported to possess numerous pharmacological activities. Paeoniflorin and glycyrrhizin are always used together for the treatment of disease in China...
Paeoniflorin is reported to possess numerous pharmacological activities. Paeoniflorin and glycyrrhizin are always used together for the treatment of disease in China clinics; however, the drug-drug interaction between glycyrrhizin and paeoniflorin is still unknown. This study investigates the effects of glycyrrhizin on the pharmacokinetics of paeoniflorin in rats. The pharmacokinetics of orally administered paeoniflorin (20 mg/kg) with or without glycyrrhizin pre-treatment (at a dose of 100 mg/kg/day for 7 days) were investigated in male Sprague-Dawley rats using LC-MS/MS. Additionally, Caco-2 cell transwell model and rat liver microsome incubation experiments were also conducted to investigate its potential mechanism. The results showed that when the rats were pre-treated with glycyrrhizin, the of paeoniflorin decreased from 59.57 ± 10.24 to 45.36 ± 8.61 ng/mL, and also decreased from 282.02 ± 35.06 to 202.29 ± 28.28 μg·h/L. The value of paeoniflorin decreased from 8.48 ± 2.01 to 5.88 ± 1.15 h ( < 0.05). The Caco-2 cell transwell experiments indicated that glycyrrhizin could increase the efflux ratio of paeoniflorin from 2.71 to 3.52, and the rat liver microsome incubation experiments showed that glycyrrhizin could significantly increase its intrinsic clearance rate from 53.7 ± 4.6 to 85.6 ± 7.1 μL/min/mg protein. These results indicated that glycyrrhizin could affect the pharmacokinetics of paeoniflorin, and it might work through decreasing the absorption of paeoniflorin by inducing the activity of or through increasing the clearance rate in rat liver by inducing the activity of CYP450 enzyme.
Topics: Animals; Biological Transport; Caco-2 Cells; Cytochrome P-450 CYP3A; Drug Interactions; Glucosides; Glycyrrhizic Acid; Humans; Male; Metabolic Clearance Rate; Microsomes, Liver; Monoterpenes; Permeability; Rats, Sprague-Dawley
PubMed: 31429612
DOI: 10.1080/13880209.2019.1651876 -
Oxidative Medicine and Cellular... 2016Nonsteroidal anti-inflammatory drugs (NSAIDs), especially cyclooxygenase-2 (COX-2) selective inhibitors, are among the most widely used drugs to treat pain and... (Review)
Review
Nonsteroidal anti-inflammatory drugs (NSAIDs), especially cyclooxygenase-2 (COX-2) selective inhibitors, are among the most widely used drugs to treat pain and inflammation. However, clinical trials have revealed that these inhibitors predisposed patients to a significantly increased cardiovascular risk, consisting of thrombosis, hypertension, myocardial infarction, heart failure, and sudden cardiac death. Thus, microsomal prostaglandin E (PGE) synthase-1 (mPGES-1), the key terminal enzyme involved in the synthesis of inflammatory prostaglandin E2 (PGE2), and the four PGE2 receptors (EP1-4) have gained much attention as alternative targets for the development of novel analgesics. The cardiovascular consequences of targeting mPGES-1 and the PGE2 receptors are substantially studied. Inhibition of mPGES-1 has displayed a relatively innocuous or preferable cardiovascular profile. The modulation of the four EP receptors in cardiovascular system is diversely reported as well. In this review, we highlight the most recent advances from our and other studies on the regulation of PGE2, particularly mPGES-1 and the four PGE2 receptors, in cardiovascular function, with a particular emphasis on blood pressure regulation, atherosclerosis, thrombosis, and myocardial infarction. This might lead to new avenues to improve cardiovascular disease management strategies and to seek optimized anti-inflammatory therapeutic options.
Topics: Animals; Cardiovascular Diseases; Cardiovascular System; Humans; Microsomes; Prostaglandin-E Synthases; Receptors, Prostaglandin; Vascular Remodeling
PubMed: 27594972
DOI: 10.1155/2016/5249086 -
Drug Metabolism and Disposition: the... Dec 2019When predicting hepatic clearance using in vitro to in vivo extrapolation (IVIVE), microsomes or hepatocytes are commonly used. Here, we examine intrinsic clearance...
When predicting hepatic clearance using in vitro to in vivo extrapolation (IVIVE), microsomes or hepatocytes are commonly used. Here, we examine intrinsic clearance values and IVIVE results in human hepatocytes and microsomes for compounds metabolized by a variety of enzymes. The great majority of CYP3A4 substrates examined had higher intrinsic clearance values in microsomes compared with hepatocytes, whereas the values were more similar between the two incubations for substrates of other enzymes. We hypothesize that this may be due to interplay between CYP3A4 and the efflux transporter P-glycoprotein, as they have been shown to exhibit coordinated regulation. When examining the prediction accuracy for substrates of other enzymes between microsomes and hepatocytes, average fold errors as well as overall error were similar, demonstrating once again that IVIVE methods are not adequately defined and understood. SIGNIFICANCE STATEMENT: For CYP3A4 substrates, microsomes give markedly higher predictive in vitro to in vivo extrapolation than for other metabolic enzymes, which is not found for hepatocytes. We hypothesize that this could be a result of CYP3A4-P-glycoprotein interplay or coordinated regulation in hepatocytes that would not be observed in microsomes.
Topics: Cytochrome P-450 CYP3A; Hepatocytes; Humans; In Vitro Techniques; Kinetics; Metabolic Clearance Rate; Microsomes, Liver; Models, Biological; Pharmaceutical Preparations; Predictive Value of Tests; Substrate Specificity
PubMed: 31551322
DOI: 10.1124/dmd.119.088427 -
PloS One 2022The intracellular distribution of copper in the liver has been investigated in dogs and humans. However, this has not been reported in cats. This study aimed to assess...
The intracellular distribution of copper in the liver has been investigated in dogs and humans. However, this has not been reported in cats. This study aimed to assess the intracellular copper distribution in liver specimens from cats with a range of hepatic copper concentrations. Twenty-nine frozen liver specimens from cats were included. Each liver specimen was divided into two pieces for overall copper quantification and tissue fractionation. The copper concentrations in liver specimens and liver fractions were measured by flame atomic absorption spectroscopy. Five specimens had copper concentrations < 100 μg/g dry weight, eight had copper concentrations between 100 and 180 μg/g, 14 had copper concentrations between 181 and 700 μg/g, and two had copper concentrations >700 μg/g. Only one specimen had positive copper staining. Regardless of the overall concentrations, copper was mostly found in the cytosolic fraction followed by the nuclear, large granule, and microsomal fractions. Our findings indicate that similarly to other species, intracellular copper is predominantly found in the cytosolic and nuclear fractions in cats. The distribution in cats with copper-loaded conditions, such as primary copper hepatopathy, was not assessed but warrants evaluation.
Topics: Animals; Cats; Cell Fractionation; Cell Nucleus; Copper; Cytosol; Female; Humans; Liver; Male; Microsomes, Liver; Spectrophotometry, Atomic
PubMed: 35157741
DOI: 10.1371/journal.pone.0264003 -
Acta Pharmacologica Sinica Apr 2022Dendrobine is the main sesquiterpene alkaloid of Dendrobium nobile Lindl, which exhibits potent neuroprotective activity. However, its metabolism and disposition are...
Dendrobine is the main sesquiterpene alkaloid of Dendrobium nobile Lindl, which exhibits potent neuroprotective activity. However, its metabolism and disposition are little known. In this study, we investigated the metabolic characteristics of dendrobine in vitro and in rats. The metabolic stability and temporal profile of metabolites formation of dendrobine were assayed in human/rat liver microsomal and S9 fractions. Dendrobine metabolites were separated and identified mainly by UPLC-Q/Orbitrap MS. After oral administration of dendrobine (50 mg/kg) to rats, the accumulative excretion rate of dendrobine in feces, urine, and bile was 0.27%, 0.52%, and 0.031%, respectively, and low systematic exposure of dendrobine (AUC = 629.2 ± 56.4 ng·h/mL) was observed. We demonstrated that the elimination of dendrobine was very rapid in liver microsomal incubation (the in vitro elimination t in rat and human liver microsomes was 1.35 and 5.61 min, respectively). Dendrobine underwent rapid and extensive metabolism; cytochrome P450, especially CYP3A4, CYP2B6, and CYP2C19, were mainly responsible for its metabolism. Aldehyde dehydrogenase, alcohol dehydrogenase and aldehyde oxidase were involved in the formation of carboxylic acid metabolites. By the aid of in-source fragmentation screening, hydrogen/deuterium exchange experiment, post-acquisition processing software, and available reference standards, 50 metabolites were identified and characterized in liver microsomal incubation and in rats. The major metabolic pathways of dendrobine were N-demethylation, N-oxidation, and dehydrogenation, followed by hydroxylation and glucuronidation. Collectively, the metabolic fate of dendrobine elucidated in this study not only yields benefits for its subsequent metabolism study but also facilitates to better understanding the mode of action of dendrobine and evaluating the pharmacologic efficiency of the high exposure metabolites.
Topics: Alkaloids; Animals; Cytochrome P-450 Enzyme System; Microsomes, Liver; Neuroprotective Agents; Rats
PubMed: 34183753
DOI: 10.1038/s41401-021-00690-9 -
Bioorganic & Medicinal Chemistry Letters Feb 2022Hepatitis B virus (HBV) core protein, the building block of the HBV capsid, plays multiple roles in viral replication, and is an attractive target for development of...
Hepatitis B virus (HBV) core protein, the building block of the HBV capsid, plays multiple roles in viral replication, and is an attractive target for development of antiviral agents with a new mechanism of action. In addition to the heteroaryldihydropyrimidines (HAPs), sulfamoylbenzamides (SBAs), dibenzothiazepine derivatives (DBTs), and sulfamoylpyrrolamides (SPAs) that inhibit HBV replication by modulation of viral capsid assembly and are currently under clinical trials for the treatment of chronic hepatitis B (CHB), other chemical structures with activity to modulate HBV capsid assembly have also been explored. Here we describe our continued optimization of a benzamide originating from our high throughput screening. A new bicyclic carboxamide lead featuring an electron deficient non-planar core structure was discovered. Evaluations of its ADMET (absorption, distribution, metabolism, excretion and toxicity) and pharmacokinetic (PK) profiles demonstrate improved metabolic stability and good bioavailability.
Topics: Animals; Antiviral Agents; Dose-Response Relationship, Drug; Hepatitis B virus; Humans; Mice; Microbial Sensitivity Tests; Microsomes, Liver; Molecular Structure; Quinolines; Structure-Activity Relationship; Viral Core Proteins; Virus Replication
PubMed: 34979256
DOI: 10.1016/j.bmcl.2021.128518 -
Chemical Research in Toxicology Feb 2018Cytochromes P450 (CYPs) oxidize alkylated amines commonly found in drugs and other biologically active molecules, cleaving them into an amine and an aldehyde. Metabolic...
Cytochromes P450 (CYPs) oxidize alkylated amines commonly found in drugs and other biologically active molecules, cleaving them into an amine and an aldehyde. Metabolic studies usually neglect to report or investigate aldehydes, even though they can be toxic. It is assumed that they are efficiently detoxified into carboxylic acids and alcohols. Nevertheless, some aldehydes are reactive and escape detoxification pathways to cause adverse events by forming DNA and protein adducts. Herein, we modeled N-dealkylations that produce both amine and aldehyde metabolites and then predicted the reactivity of the aldehyde. This model used a deep learning approach previously developed by our group to predict other types of drug metabolism. In this study, we trained the model to predict N-dealkylation by human liver microsomes (HLM), finding that including isozyme-specific metabolism data alongside HLM data significantly improved results. The final HLM model accurately predicted the site of N-dealkylation within metabolized substrates (97% top-two and 94% area under the ROC curve). Next, we combined the metabolism, metabolite structure prediction, and previously published reactivity models into a bioactivation model. This combined model predicted the structure of the most likely reactive metabolite of a small validation set of drug-like molecules known to be bioactivated by N-dealkylation. Applying this model to approved and withdrawn medicines, we found that aldehyde metabolites produced from N-dealkylation may explain the hepatotoxicity of several drugs: indinavir, piperacillin, verapamil, and ziprasidone. Our results suggest that N-dealkylation may be an under-appreciated bioactivation pathway, especially in clinical contexts where aldehyde detoxification pathways are inhibited. Moreover, this is the first report of a bioactivation model constructed by combining a metabolism and reactivity model. These results raise hope that more comprehensive models of bioactivation are possible. The model developed in this study is available at http://swami.wustl.edu/xenosite/ .
Topics: Aldehydes; Amines; Dealkylation; Humans; Indinavir; Liver; Microsomes, Liver; Models, Molecular; Molecular Structure; Piperacillin; Piperazines; Thiazoles; Verapamil
PubMed: 29355304
DOI: 10.1021/acs.chemrestox.7b00191