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Pasini E, Comini L, Dioguardi FS, Grossetti F, Olivares A, Zanelli E, Aquilani R, Scalvini S. Hypoalbuminemia as a marker of protein metabolism disarrangement in patients with stable chronic heart failure. Minerva Med 2020; 111:226-238. [PMID: 32166926 DOI: 10.23736/s0026-4806.20.06244-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND Despite therapeutic advances, chronic heart failure (CHF)-related mortality and hospitalization is still unacceptably high. Evidence shows that muscular wasting, sarcopenia, cachexia are independent predictors of mortality and morbidity in CHF and are signs of protein metabolism disarrangement (PMD), which involve all body proteins including circulating one. We postulate that circulating human serum albumin (HSA) could be a marker of PMD and catabolic low-grade inflammation (LGI) in CHF patients. METHODS One hundred sixty-six stable CHF patients (73% males), with optimized therapy referred to cardiac rehabilitation, were retrospectively divided into three groups based on their HSA concentration: ≥3.5 g/dL (normal value), 3.2-3.49 g/dL (low value); ≤3.19 g/dL (severe value). Hematochemical analyses (including circulating proteins and inflammatory markers) and body mass composition (by Bioelectrical Impedance Vector Analysis) were collected and compared. Correlations and multivariate regression were performed. RESULTS Despite being overweight (BMI=27 kg/m2), 75% of patients had reduced HSA (<3.5 g/dL) with suspectable sarcopenia, and 35% of all patients had remarkably lower albumin concentrations (<3.19 g/dL). Hypoalbuminemic patients were disable, older, with reduced muscular proteins, bilirubin and hemoglobin, increased extracellular water and LGI (P<0.01). HSA correlated with all of these parameters (all: P<0.01). Age, LGI, BMI, free-fat Mass, and bilirubin were independent predictors of HSA concentration. All these findings were male-dependent. CONCLUSIONS HSA could be considered a simple marker of PMD and LGI in CHF patients. Evaluation of PMD and gender differences should be considered in new CHF clinical trials.
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Affiliation(s)
- Evasio Pasini
- Cardiac Rehabilitation of the Institute of Lumezzane, Clinical Scientific Institutes Maugeri IRCCS, Brescia, Italy -
| | - Laura Comini
- Clinical Scientific Institutes Maugeri IRCCS, Scientific Direction of the Institute of Lumezzane, Brescia, Italy
| | | | | | - Adriana Olivares
- Clinical Scientific Institutes Maugeri IRCCS, Scientific Direction of the Institute of Lumezzane, Brescia, Italy
| | - Emanuela Zanelli
- Cardiac Rehabilitation of the Institute of Lumezzane, Clinical Scientific Institutes Maugeri IRCCS, Brescia, Italy
| | - Roberto Aquilani
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Simonetta Scalvini
- Cardiac Rehabilitation of the Institute of Lumezzane, Clinical Scientific Institutes Maugeri IRCCS, Brescia, Italy
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Nugbienyo L, Malinina Y, Garmonov S, Kamencev M, Salahov I, Andruch V, Moskvin L, Bulatov A. Automated sugaring-out liquid-liquid extraction based on flow system coupled with HPLC-UV for the determination of procainamide in urine. Talanta 2017; 167:709-713. [DOI: 10.1016/j.talanta.2017.02.051] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 02/22/2017] [Indexed: 10/20/2022]
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Hanging Drop, A Best Three-Dimensional (3D) Culture Method for Primary Buffalo and Sheep Hepatocytes. Sci Rep 2017; 7:1203. [PMID: 28446763 PMCID: PMC5430879 DOI: 10.1038/s41598-017-01355-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 03/27/2017] [Indexed: 02/07/2023] Open
Abstract
Livestock, having close resemblance to humans, could be a better source of primary hepatocytes than rodents. Herein, we successfully developed three-dimensional (3D) culturing system for primary sheep and buffalo hepatocytes. The 3D-structures of sheep hepatocytes were formed on the fifth-day and maintained until the tenth-day on polyHEMA-coated plates and in hanging drops with William’s E media (HDW). Between the cultured and fresh cells, we observed a similar expression of GAPDH, HNF4α, ALB, CYP1A1, CK8 and CK18. Interestingly, a statistically significant increase was noted in the TAT, CPS, AFP, AAT, GSP and PCNA expression. In buffalo hepatocytes culture, 3D-like structures were formed on the third-day and maintained until the sixth-day on polyHEMA and HDW. The expression of HNF4α, GSP, CPS, AFP, AAT, PCNA and CK18 was similar between cultured and fresh cells. Further, a statistically significant increase in the TAT and CK8 expression, and a decrease in the GAPDH, CYP1A1 and ALB expression were noted. Among the culture systems, HDW maintained the liver transcript markers more or less similar to the fresh hepatocytes of the sheep and buffalo for ten and six days, respectively. Taken together, hanging drop is an efficient method for 3D culturing of primary sheep and buffalo hepatocytes.
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Timofeeva I, Medinskaia K, Nikolaeva L, Kirsanov D, Bulatov A. Stepwise injection potentiometric determination of caffeine in saliva using single-drop microextraction combined with solvent exchange. Talanta 2016; 150:655-60. [DOI: 10.1016/j.talanta.2016.01.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 12/29/2015] [Accepted: 01/02/2016] [Indexed: 11/29/2022]
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Poggesi I, Benedetti MS, Whomsley R, Le Lamer S, Molimard M, Watelet JB. Pharmacokinetics in special populations. Drug Metab Rev 2009; 41:422-54. [PMID: 19601721 DOI: 10.1080/10837450902891527] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Pharmacokinetics are typically dependent on a variety of physiological variables (e.g., age, ethnicity, or pregnancy) or pathological conditions (e.g., renal and hepatic insufficiency, cardiac dysfunction, obesity, etc.). The influence of some of these conditions has not always been thoroughly assessed in the clinical studies of antiallergic drugs. However, the knowledge of the physiological grounds of the pharmacokinetics can provide some insight for predicting the potential alterations and guiding the initial prescription strategies. It is important to recognize that both pharmacokinetic and pharmacodynamic differences between populations should be considered. The available information on drugs used for the therapy of allergic diseases is reviewed in this chapter.
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Affiliation(s)
- Italo Poggesi
- Clinical Pharmacology/Modeling & Simulation, GlaxoSmithKline, Verona, Italy.
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6
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van Velzen EJJ, Westerhuis JA, van Duynhoven JPM, van Dorsten FA, Grün CH, Jacobs DM, Duchateau GSMJE, Vis DJ, Smilde AK. Phenotyping Tea Consumers by Nutrikinetic Analysis of Polyphenolic End-Metabolites. J Proteome Res 2009; 8:3317-30. [DOI: 10.1021/pr801071p] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ewoud J. J. van Velzen
- Biosystems Data Analysis, Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands, and Unilever Research and Development, Olivier van Noortlaan 120, 3133 AT Vlaardingen, The Netherlands
| | - Johan A. Westerhuis
- Biosystems Data Analysis, Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands, and Unilever Research and Development, Olivier van Noortlaan 120, 3133 AT Vlaardingen, The Netherlands
| | - John P. M. van Duynhoven
- Biosystems Data Analysis, Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands, and Unilever Research and Development, Olivier van Noortlaan 120, 3133 AT Vlaardingen, The Netherlands
| | - Ferdi A. van Dorsten
- Biosystems Data Analysis, Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands, and Unilever Research and Development, Olivier van Noortlaan 120, 3133 AT Vlaardingen, The Netherlands
| | - Christian H. Grün
- Biosystems Data Analysis, Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands, and Unilever Research and Development, Olivier van Noortlaan 120, 3133 AT Vlaardingen, The Netherlands
| | - Doris M. Jacobs
- Biosystems Data Analysis, Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands, and Unilever Research and Development, Olivier van Noortlaan 120, 3133 AT Vlaardingen, The Netherlands
| | - Guus S. M. J. E. Duchateau
- Biosystems Data Analysis, Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands, and Unilever Research and Development, Olivier van Noortlaan 120, 3133 AT Vlaardingen, The Netherlands
| | - Daniël J. Vis
- Biosystems Data Analysis, Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands, and Unilever Research and Development, Olivier van Noortlaan 120, 3133 AT Vlaardingen, The Netherlands
| | - Age K. Smilde
- Biosystems Data Analysis, Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands, and Unilever Research and Development, Olivier van Noortlaan 120, 3133 AT Vlaardingen, The Netherlands
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Isojärvi JI, Turkka J, Pakarinen AJ, Kotila M, Rättyä J, Myllylä VV. Thyroid function in men taking carbamazepine, oxcarbazepine, or valproate for epilepsy. Epilepsia 2001; 42:930-4. [PMID: 11488894 DOI: 10.1046/j.1528-1157.2001.042007930.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE Antiepileptic drugs (AEDs) may affect serum thyroid hormone concentrations. This study aimed to evaluate thyroid function in men taking carbamazepine (CBZ), oxcarbazepine (OCBZ), or valproate (VPA) for epilepsy. METHODS Ninety men with epilepsy (40 taking CBZ, 29 taking OCBZ, and 21 taking VPA monotherapy) and 25 control subjects participated in the study. After clinical examination, a blood sample for hormone, gamma-glutamyl-transferase (GGT) and antibody (ab) assays was obtained. RESULTS Serum thyroxine (T4) and free thyroxine (FT4) concentrations were low in men taking CBZ or OCBZ. Forty-five percent of men taking CBZ and 24% of men taking OCBZ had serum T4 and/or FT4 levels below the reference range. However, no correlations were found between T4 or FT4 and GGT concentrations in men taking CBZ or OCBZ. Thirteen percent of men taking CBZ, 17% of men taking OCBZ, and 6% of control men had increased levels of thyroid peroxidase (TPO)-ab and/or thyroglobulin (TG)-ab, but these were not associated with altered serum thyroid hormone concentrations. Serum triiodothyronine and thyrotropin levels in men taking CBZ or OCBZ were normal. In men taking VPA, the concentrations of thyroid hormones, thyrotropin, and antithyroid ab were normal. CONCLUSIONS Serum thyroid hormone concentrations are low in CBZ- or OCBZ-treated men. However, these low levels do not seem to be due to liver enzyme induction or activation of immunologic mechanisms. Therefore, interference with hypothalamic regulation of thyroid function by CBZ and OCBZ seems possible. VPA does not have any significant effects on thyroid function.
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Affiliation(s)
- J I Isojärvi
- Department of Neurology, University of Oulu, Oulu, Finland.
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Allen E, Tsanaclis LM, Wroe SJ, Reece PA, Sedman AJ. Gabapentin does not affect antipyrine clearance. J Clin Pharmacol 1999; 39:934-5. [PMID: 10471984 DOI: 10.1177/00912709922008551] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The effect of gabapentin on antipyrine clearance was assessed in 12 healthy male volunteers, using a known enzyme inducer, phenytoin, as control. Subjects received gabapentin 400 mg or phenytoin 100 mg three times daily for 2 weeks. Antipyrine tests were performed before, during, and after treatment with gabapentin or phenytoin. In contrast to phenytoin, chronic administration of gabapentin did not affect antipyrine clearance. Gabapentin appears to have little potential for drug interactions.
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Affiliation(s)
- E Allen
- Guy's Drug Research Unit, London, United Kingdom
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9
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Tanaka E, Ishikawa A, Horie T. In vivo and in vitro trimethadione oxidation activity of the liver from various animal species including mouse, hamster, rat, rabbit, dog, monkey and human. Hum Exp Toxicol 1999; 18:12-6. [PMID: 10025363 DOI: 10.1177/096032719901800102] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Trimethadione (TMO) has the properties required of a probe drug for the evaluation of hepatic drug-oxidizing capacity and, in this study, we have summarized the in vivo and in vitro metabolism of TMO in various animal species including mouse, hamster, rat, rabbit, dog, monkey and human. In the in vivo study, the plasma TMO level was measured after intravenous or oral (human) administration of TMO at a dose of 4 mg/kg to various animal species. The rate of TMO metabolic clearance in these animal species in vivo was in the order mouse > hamster > rat > rabbit > dog > monkey > human. In the in vitro study, species differences were observed in the cytochrome P450 (P450) content and drug-oxidizing enzyme activity. The content of P450 was monkey> mouse > dog > rabbit > hamster > rat > human. On the other hand, TMO N-demethylation was in the order mouse > hamster > rat > rabbit > dog > monkey > human. There was a good correlation between the mean total body clearance of TMO (in vivo) and the mean TMO N-demethylase activity (in vitro) (y=1.7 x +0.11, r=0.965, P < 0.001). These results show that TMO is a probe agent with metabolic and pharmacokinetic characteristics making it attractive for the in vivo and in vitro characterization of metabolic activity in various animal species.
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Affiliation(s)
- E Tanaka
- Institute of Community Medicine, University of Tsukuba, Ibaraki-ken, Japan
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10
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Isojärvi JI, Pakarinen AJ, Myllylä VV. Basic haematological parameters, serum gamma-glutamyl-transferase activity, and erythrocyte folate and serum vitamin B12 levels during carbamazepine and oxcarbazepine therapy. Seizure 1997; 6:207-11. [PMID: 9203249 DOI: 10.1016/s1059-1311(97)80007-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Basic haematologic parameters and serum gamma-glutamyl-transferase (GGT) activity were evaluated in a five-year prospective follow-up study of 25 patients with newly diagnosed epilepsy starting treatment with carbamazepine. In addition, we evaluated the effects of replacing carbamazepine by oxcarbazepine on these parameters, erythrocyte folate concentrations and serum vitamin B12 levels in 12 male patients with epilepsy. The mean white blood cell count (WBC) and red blood cell count decreased after 2 months carbamazepine therapy, and remained at this lower level during the first 5 years of medication. The mean erythrocyte volume (MCV) and the serum GGT activity increased progressively during carbamazepine treatment. The serum GGT activity decreased after replacing carbamazepine by oxcarbazepine indicating a normalization of the liver P450 enzyme system induction. Concomitantly, the erythrocyte folate concentrations and serum levels of vitamin B12 increased, and the WBC increased and MCV decreased. It is probable that the changes in folate metabolism and serum vitamin B12 concentrations are due to normalization of the liver P450 enzyme system induction after the change of medication. The haematologic changes during carbamazepine medication, and their normalization after replacing carbamazepine by oxcarbazepine are possibly related to changes in folate and vitamin B12 metabolism.
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Affiliation(s)
- J I Isojärvi
- Department of Neurology, University of Oulu, Finland
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11
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Tanaka E, Ishikawa A, Abei M, Kobayashi S. Trimethadione as a probe drug to estimate hepatic oxidizing capacity in humans. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART C, PHARMACOLOGY, TOXICOLOGY & ENDOCRINOLOGY 1996; 115:211-6. [PMID: 9375358 DOI: 10.1016/s0742-8413(96)00102-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Trimethadione (TMO) has the properties required of probe drugs for the evaluation of hepatic drug-oxidizing capacity in humans in vivo. TMO is demethylated to dimethadione (DMO), its only metabolite, in the liver after oral administration. Involvement of two cytochrome P450's--CYP2C9 and 3A4--in TMO metabolism has been seen in humans, but involvement of 1A2 is not clearly established. In humans with various types of liver disease and hepatectomy, the serum DMO/TMO ratios, which were measured on blood samples obtained by a single collection 4 hr after oral administration of TMO, correlated well with the degree of hepatic damage. This finding suggests that TMO may be used as a probe drug in the rapid determination of the functional reserve mass of the liver as well as hepatic drug-oxidizing capacity in humans in vivo.
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Affiliation(s)
- E Tanaka
- Institute of Community Medicine, University of Tsukuba, Ibaraki-ken, Japan
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12
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Soto J, Sacristan JA, Alsar MJ. Use of salivary caffeine tests to assess the inducer effect of a drug on hepatic metabolism. Ann Pharmacother 1996; 30:736-9. [PMID: 8826551 DOI: 10.1177/106002809603000705] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
OBJECTIVE To validate the use of successive salivary caffeine tests in evaluating how long inducer drugs affect hepatic metabolism. The time course of the inducer effect of rifampin found in other studies using different methodologies was chosen as the time course of reference. DESIGN Open-label, prospective, longitudinal study. SETTING A university hospital. PARTICIPANTS Five healthy volunteers. MAIN OUTCOME MEASURES Rifampin 600 mg/d was administered for 21 days. Anhydrous caffeine 300 mg was concurrently administered on each study day. Salivary caffeine tests were carried out on the following days: predose (baseline), and days 1, 5, 9, 13, and 17. Salivary tests were performed for up to 13 days after the last dose of rifampin (study days 21, 25, 29, and 33). RESULTS The mean systemic caffeine clearance was increased for up to 17 days after the intake of rifampin, reaching the maximum inducer effect between days 5 and 9, and returning to previous values progressively during several days after rifampin was discontinued. CONCLUSIONS Our results suggest that successive salivary caffeine measurements could be a safe, reliable, noninvasive, and suitable test for exploring the time course of the inducer effect of drugs on hepatic metabolism activity.
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Affiliation(s)
- J Soto
- Clinical Pharmacology Unit, Hospital Santa Cruz, (Cantabria), Spain
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Engel G, Hofmann U, Heidemann H, Cosme J, Eichelbaum M. Antipyrine as a probe for human oxidative drug metabolism: identification of the cytochrome P450 enzymes catalyzing 4-hydroxyantipyrine, 3-hydroxymethylantipyrine, and norantipyrine formation. Clin Pharmacol Ther 1996; 59:613-23. [PMID: 8681486 DOI: 10.1016/s0009-9236(96)90001-6] [Citation(s) in RCA: 125] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND AND OBJECTIVE Antipyrine has been widely used as a probe drug for human oxidative drug metabolism. To evaluate the role of antipyrine as a model drug, we have identified the cytochrome P450 enzymes involved in 4-hydroxyantipyrine, 3-hydroxymethylantipyrine, and norantipyrine formation. METHODS We used the following methods for this study: (1) determination of enzyme kinetics for antipyrine metabolite formation in human liver microsomes, (2) inhibition studies with antibodies and inhibitors, and (3) formation of metabolites by stable expressed human P450 enzymes. RESULTS Antipyrine biotransformation could be described by Michaelis-Menten kinetics: norantipyrine: maximum rate of metabolite formation (Vmax), 0.91 +/- 0.04 nmol . mg-1 . min-1; Michaelis-Menten constant (Km), 19.0 +/- 0.8 mmol/L; 4-hydroxyantipyrine: Vmax, 1.54 +/- 0.08 nmol . mg-1 . min-1;Km,39.6 +/- 2.5 mmol/L. Antibodies against CYP3A4 inhibited the formation of 4-hydroxyantipyrine by 25% to 65%. LKM-2 antibodies (anti-CYP2C) caused a 75% to 100% inhibition of norantipyrine and a 58% to 80% inhibition of 3-hydroxymethylantipyrine formation. Sulfaphenazole inhibited the formation of 3-hydroxymethylantipyrine and norantipyrine by about 50%. Furafylline and fluvoxamine inhibited norantipyrine, 4-hydroxyantipyrine, and 3-hydroxymethylantipyrine formation by about 30%, 30%, and 50%, respectively. Ketoconazole reduced formation of norantipyrine, 3-hydroxymethylantipyrine, and 4-hydroxyantipyrine by up to 80%. Formation in stable expressed enzymes indicated involvement of CYP1A2, CYP2B6, CYP2C, and CYP3A4 in metabolite formation. CONCLUSION Antipyrine metabolites are formed by at least six hepatic cytochrome P450 enzymes (CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C18, and CYP3A4). 4-Hydroxylation is mainly catalyzed by CYP3A4 and, to a lesser extent, by CYP1A2. The CYP2C subfamily contains the predominant enzymes for norantipyrine formation, and CYP1A2 is also involved. Formation of 3-hydroxymethylantipyrine is mediated by CYP1A2 and CYP2C9. Because several cytochrome P450 enzymes are involved in the formation of each metabolite, antipyrine is not well suited as a probe for distinct human cytochrome P450 enzymes.
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Affiliation(s)
- G Engel
- Fischer-Bosch-Institut für Klinische Pharmakologie, Stuttgart, Germany
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Damani LA, Nnane IP. The assessment of flavin-containing monooxygenase activity in intact animals. DRUG METABOLISM AND DRUG INTERACTIONS 1996; 13:1-28. [PMID: 8902428 DOI: 10.1515/dmdi.1996.13.1.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A large number of drug metabolising enzymes with different substrate specificities and induction and inhibition characteristics have been described, suggesting that specific test drugs, i.e. probes, should be used for assessing the activity of distinct metabolising enzymes. The flavin-containing monooxygenase (FMO) and cytochrome P-450 (P-450) are the two main microsomal enzyme systems involved in the oxidation of xenobiotics. FMO is present in liver and other tissues of most vertebrates. It catalyses the oxidation of a wide range of xenobiotics, especially soft nucleophiles bearing nitrogen and sulphur centres. There is substantial information on both in vitro and in vivo probes for cytochrome P-450. For example antipyrine has been widely used for assessing the activity of P-450 in vivo by utilising pharmacokinetic parameters as indices of enzyme activity. In more recent years, isozyme specific probes have also been developed for some of the P-450s. Whereas a number of substrates are available for measuring FMO activity in vitro (e.g. N,N-dimethylaniline), probes for assessing FMO activity in vivo are limited. In this review a background to the use of in vitro and in vivo probes for assessing the activity of FMO is presented, and approaches and criteria for development of potential pharmacokinetic probes for FMO are described. Preliminary data on the development of ethyl methyl sulphide (EMS) and trimethylamine (TMA) as potential pharmacokinetic probes for assessing FMO activity in rats are discussed in detail. Clinical implications of modulation of FMO activity are discussed, and arguments presented as to why the development of FMO probes for use in man will be useful additions to the range of other compounds available for assessment of liver metabolic function.
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Affiliation(s)
- L A Damani
- Department of Pharmacy, Faculty of Medicine, Chinese University of Hong Kong, Shatin, N.T., Hong Kong
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15
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Jacqz-Aigrain E, Panserat S, Sica L, Krishnamoorthy R. Molecular genetics of cytochrome P450 IID. Anomalies of drug metabolism. Clin Rev Allergy Immunol 1995; 13:211-21. [PMID: 8535928 DOI: 10.1007/bf02771762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Engel G, Hofmann U, Eichelbaum M. Highly sensitive and specific gas chromatographic-tandem mass spectrometric method for the determination of trace amounts of antipyrine metabolites in biological material. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL APPLICATIONS 1995; 666:111-6. [PMID: 7655608 DOI: 10.1016/0378-4347(94)00563-k] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A highly sensitive and specific gas chromatographic-tandem mass spectrometric method was developed for the determination of the antipyrine (INN: phenazone) metabolites, norantipyrine, 4-hydroxyantipyrine and 3-hydroxy-methylantipyrine, in biological material. Deuterated analogues of the metabolites were used as internal standards. The method has a limit of quantitation of 5 ng per sample for the determination of norantipyrine, 4-hydroxy-antipyrine and 3-hyddroxymethylantipyrine with coefficients of variation of 19.4, 14.6 and 20.7%, respectively. Precision and accuracy are good over the whole range measured (5-500 ng/sample) with a coefficient of variation, respectively error of determination < or = 20%. Due to its high sensitivity the method can be used to study the formation of these metabolites in microsomal preparations containing only 100 micrograms of protein.
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Affiliation(s)
- G Engel
- Dr. Margarete Fischer-Bosch-Institut für Klinische Pharmakologie, Stuttgart, Germany
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17
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Sinués B, Gazulla J, Bernal ML, Lanuza J, Fanlo A, Saenz MA, Barolome M. Six mutagenicity assays in exposure biomonitoring of patients receiving carbamazepine for epilepsy or trigeminal neuralgia. Mutat Res 1995; 334:259-65. [PMID: 7885380 DOI: 10.1016/0165-1161(95)90019-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The mutagenic potential of carbamazepine (CBZ) therapy has been studied in 37 patients undergoing long-term treatment with this drug. Of the total group, 23 patients suffered from epilepsy and 14 from trigeminal neuralgia. Thirty-one healty subjects served as controls. Six mutagenicity assays with different end-points were performed. The possible cytogenetic alterations were evaluated by analyzing sister-chromatid exchange frequencies (SCE), chromosome aberrations (CA), micronuclei (MN), proliferation indices (PRI), and mitotic indices. The Salmonella assay with and without microsomal activation served to measure urinary mutagenicity. The results show that CBZ leads to an increase in SCE (p < 0.01) and PRI (p < 0.05) but had no effect on the other cytogenetic parameters. CBZ was negative in the urine mutagenicity test. Plasma levels of total CBZ, free CBZ and CBZ-10,11-epoxide did not correlate with the cytogenetic alterations. Even though folic acid and gamma-glutamyltranspeptidase were significantly different in patients and controls, there was no significant association between these values and SCE or PRI. Patients with epilepsy and those with trigeminal neuralgia did not differ with respect to the end-points analyzed.
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Affiliation(s)
- B Sinués
- Department of Pharmacology and Physiology, Faculty of Medicine, University of Zaragoza, Spain
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18
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Patel SB, Khatkhatay I, Desai MP, Betrabet SS, Toddywalla VS. A sensitive ELISA for 6 beta-hydroxycortisol in urine using enzyme penicillinase (beta-lactamase). J Steroid Biochem Mol Biol 1994; 48:293-6. [PMID: 8142307 DOI: 10.1016/0960-0760(94)90159-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A sensitive and specific, enzyme labelled immunosorbent assay (ELISA) for 6 beta-hydroxycortisol in diluted urine using penicillinase was developed. 6 beta-Hydroxycortisol-21-hemisuccinate was conjugated with enzyme penicillinase. Antibody immobilized on a polyvinylchloride ELISA plate (Dynatech) was used for separation of bound from free ligand. The sensitivity of the assay was between 2.0-3.0 pg per well and recovery of 6 beta-hydroxycortisol from urine ranged between 85.0-108.0%. The assay is simple, rapid and precise.
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Affiliation(s)
- S B Patel
- Institute for Research in Reproduction (ICMR), Parel, Bombay, India
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Damanhouri ZA, Tayeb OS. A comparative study of liver mixed function oxidases in camels (Camelus dromedarius), guinea pigs (Cavia porcellus) and rats (Rattus norvegicus). COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. C, COMPARATIVE PHARMACOLOGY AND TOXICOLOGY 1993; 105:487-91. [PMID: 7693392 DOI: 10.1016/0742-8413(93)90090-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
1. The activities of the drug-metabolizing enzymes, benzphetamine N-demethylase, 7-ethoxycoumarin O-deethylase and dicoumarol oxidation have been measured in vitro in the liver of camels, guinea pigs and rats. 2. In these species, levels of hepatic microsomal parameters namely microsomal protein, cytochrome P450, cytochrome b5 and NADPH-cytochrome c reductase have also been determined. 3. In general, camels seemed to have the lowest enzyme activity when compared to rats and guinea pigs. 4. Some sex differences were observed in the levels of enzymes studied. In rats and guinea pigs, males had higher benzphetamine N-demethylase than females. However, in camels and guinea pigs, females had higher 7-ethoxycoumarin O-deethylase when compared to males.
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Affiliation(s)
- Z A Damanhouri
- Department of Pharmacology, Faculty of Medicine and Allied Sciences, King Fahad Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
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20
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von Moltke LL, Abernethy DR, Kaplan MM, Greenblatt DJ. Antipyrine kinetics in patients with primary biliary cirrhosis. J Clin Pharmacol 1993; 33:75-7. [PMID: 8429118 DOI: 10.1002/j.1552-4604.1993.tb03907.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Fourteen antimitochrodrial antibody-positive patients (13 women, 1 man) with biopsy-proven primary biliary cirrhosis, aged 40 to 71 years (mean, 57 years) weighing 43 to 102 kg (mean, 63 kg), along with 14 age- and sex-matched healthy controls, received a single 1.0- to 1.2-g dose of intravenous antipyrine. Plasma antipyrine levels were determined during a 12- to 24-hour period. Patients' mean serum chemistry values were: albumin, 3.9 g/dL (range, 3.1-4.4) and total bilirubin, 1.9 mg/dL (range, 0.3-10.9). Seven of the fourteen patients had cirrhosis. Mean kinetic variables for antipyrine in controls and primary biliary cirrhosis patients were: Vd, .54 versus .49 L/kg; half-life, 12.0 versus 15.1 hours (P < .07); clearance, .55 versus .41 mL/min/kg (P < .04). Within the primary biliary cirrhosis group, there was no correlation between total bilirubin and clearance (r = .09), nor did clearance vary significantly among histologic categories. Clearance of antipyrine in primary biliary cirrhosis patients is reduced by an average of 25%, but the clinical prognosticators of serum bilirubin levels and histologic grade do not correlate with or predict the degree of clearance impairment.
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Affiliation(s)
- L L von Moltke
- Tufts University School of Medicine, Boston, Massachusetts 02111
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21
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Franco G, Lorena M, Ghittori S. Occupational Exposure of Operating-Theater Personnel to Isoflurane and Nitrous Oxide. ACTA ACUST UNITED AC 1992. [DOI: 10.1080/1047322x.1992.10388068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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22
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Hoyle VR, Gilbert PJ, Troke JA, Vose CW, Nicholson JK. Studies on the biochemical effects of the aldose reductase inhibitor 2,7-difluorospirofluorene-9,5'-imidazolidine-2',4'-dione (Al 1576, HOE 843). Detection of D-glucaric and D-glucuronic acid excretion by high resolution 1H and 13C NMR spectroscopy. Biochem Pharmacol 1992; 44:231-41. [PMID: 1642638 DOI: 10.1016/0006-2952(92)90005-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The effects of two aldose reductase inhibitors on the biochemical composition of rat urine were investigated using high resolution 1H and 13C NMR spectroscopy. We report the elevated excretion of D-glucaric acid (DGA) and D-glucuronic acid (GCA) following treatment with 2,7-difluorospirofluorene-9,5'-imidazolidine-2'4'-dione (Imirestat, IM, Al 1576, HOE 843) at 50 mg/kg/day for 1 month, but not with 3-4-bromo-2-fluorobenzyl-4-oxo-3-phthalazine-1-ylacetic acid (Ponalrestat, Statil), dosed at 50 mg/kg/day for 2 weeks. Sugar aciduria was also detected following treatment with the cytochrome P450 inducer phenobarbitone (PB) at 45 mg/kg/day for 1 month, although the qualitative and quantitative pattern of excretion of sugar acids differed greatly between the IM and PB treatment groups. The levels of GCA excreted are elevated 11-fold by IM treatment from 19.0 to 210.0 mumol/24 hr, but only 2.5-fold by PB, from 9.7 to 23.9 mumol/24 hr. DGA was not detectable in control urine, although levels did increase by 30% during the study from 7.5 to 10.9 mumol/24 hr, between day 8 and day 29, with IM treatment, and by 60% from 1.7 to 4.9 mumol/24 hr following PB administration for the same time period. This predominant elevation of DGA and GCA caused by IM treatment far exceeds previous records. In contrast, PB treatment resulted in an increase in intensity of a number of partially resolved sugar resonances, but at a much lower level than resulted from IM treatment. A raised level of DGA and GCA is usually associated with hepatic P450 induction; however, we report here profound DGA and GCA uria as a result of the inhibition of the aldehyde reductase, hexonate dehydrogenase (EC 1.1.1.19, EC 1.1.1.20). This mechanism is not closely linked to P450 induction, corroborating the current view that elevated excretion of DGA is not a reliable indicator of hepatic enzyme induction. This study further demonstrates the use of high resolution NMR spectroscopy in the detection of a novel biochemical effect which may go unnoticed during routine clinical chemistry tests.
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Affiliation(s)
- V R Hoyle
- Department of Chemistry, Birkbeck College, London, U.K
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23
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Tanaka E, Ishikawa A, Yamamoto Y, Uchida E, Kobayashi S, Yasuhara H, Misawa S. Simplified approach for evaluation of hepatic drug-oxidizing capacity with a simultaneous measurement of caffeine and its primary demethylated metabolites in carbon tetrachloride-intoxicated rats. Xenobiotica 1992; 22:535-41. [PMID: 1413868 DOI: 10.3109/00498259209053116] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
1. Prediction of hepatic injury from changes in blood concentrations of caffeine (CA) and its three primary metabolites (theobromine: TB; paraxanthine: PX; theophylline; TP) after CA administration has been studied in carbon tetrachloride (CCl4)-intoxicated rats. 2. The plasma half-life (t1/2) of CA (10 mg/kg, oral) was increased, and total body clearance (CL) decreased, in CCl4-treated rats; the apparent volume of distribution (Vd) was relatively unchanged. 3. The ratios of CA to the three metabolites (TB/CA, PX/CA, TP/CA) were significantly decreased compared to those of controls. 4. There were good correlations between the ratios of TB/CA, PX/CA, and TP/CA and CL of CA (TB/CA; r = 0.944 at 1 h, r = 0.942 at 2 h: PX/CA; r = 0.974 at 1 h, r = 0.923 at 2 h: TP/CA; r = 0.866 at 1 h, r = 0.962 at 2 h). 5. Results indicate that it is possible to evaluate hepatic drug-oxidizing capacity by measuring the ratio of CA to its metabolites, using single blood sampling 1 or 2 h after CA administration in CCl4-intoxicated rats.
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Affiliation(s)
- E Tanaka
- Institute of Community Medicine, University of Tsukuba, Japan
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24
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Calandre EP, Sinués Porta B, García de la Calzada D. The effect of chronic phenytoin treatment on serum lipid profile in adult epileptic patients. Epilepsia 1992; 33:154-7. [PMID: 1346382 DOI: 10.1111/j.1528-1157.1992.tb02299.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and very-low-density lipoprotein cholesterol, apolipoproteins A, A1, and B and gamma-glutamyltransferase (ggt) serum concentrations were measured in 100 adult epileptic patients receiving chronic phenytoin (PHT) treatment and in 100 control subjects. In relation to controls, patients showed higher HDL cholesterol, apolipoproteins A and A1, and ggt levels and lower LDL cholesterol and apolipoprotein B values; the significance of the results was greater in women than in men. Among patients, ggt levels were positively correlated with PHT plasma concentrations; likewise, a negative correlation was found between the apolipoprotein A/A1 ratio and the PHT and ggt plasma levels, and a positive correlation between the apolipoprotein A/A1 ratio and the LDL/HDL cholesterol ratio. These data indicate that PHT exerts a beneficial effect on the serum lipids profile.
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Affiliation(s)
- E P Calandre
- Clinical Pharmacology Department, University Hospital, Granada, Spain
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25
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Affiliation(s)
- B H Ali
- Department of Veterinary Medicine, Pharmacology and Toxicology, University of Khartoum, Sudan
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26
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Larkin JG, Binnie CD, Brodie MJ. Calcium antagonism: A role in the treatment of epilepsy? ACTA ACUST UNITED AC 1992. [DOI: 10.1016/s0896-6974(05)80019-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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27
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Mansor SM, Ward SA, Edwards G. The effect of malaria infection on antipyrine metabolite formation in the rat. Biochem Pharmacol 1991; 41:1264-6. [PMID: 2009102 DOI: 10.1016/0006-2952(91)90669-v] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We have shown that malaria infection can impair selectively the formation of antipyrine metabolites in the rat. During malaria, a significant increased urinary levels of unchanged antipyrine was observed (control: 1.7 +/- 0.4 vs test: 8.1 +/- 1.1% of dose, P less than 0.001). This was associated with significantly decreased excretion of 3-hydroxymethylantipyrine (control: 24.5 +/- 1.2 vs test: 21.4 +/- 0.7%, P less than 0.001) and 4-hydroxyantipyrine (control: 20.1 +/- 0.9 vs test: 15.5 +/- 1.3%, P less than 0.001) but not norantipyrine compared to control. Following treatment of the malaria infection with halofantrine, only the formation of 3-hydroxymethylantipyrine (control: 25.2 +/- 0.9 vs test: 24.1 +/- 0.6%, P less than 0.05) is impaired. The implications of these findings in relation to metabolism of other antimalarial drugs during malaria remains to be elucidated. Further work is needed to determine the changes in the pharmacokinetics of AP and its metabolites before, during and after MI in the rat in order to give a better insight into the effect of MI on hepatic drug metabolism.
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Affiliation(s)
- S M Mansor
- Department of Pharmacology, Therapeutics-University of Liverpool, U.K
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28
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Larkin JG, McKee PJ, Forrest G, Beastall GH, Park BK, Lowrie JI, Lloyd P, Brodie MJ. Lack of enzyme induction with oxcarbazepine (600 mg daily) in healthy subjects. Br J Clin Pharmacol 1991; 31:65-71. [PMID: 2015172 PMCID: PMC1368413 DOI: 10.1111/j.1365-2125.1991.tb03858.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
1. Oxcarbazepine (OXC), the 10-keto analogue of carbamazepine (CBZ), has similar anticonvulsant efficacy and possibly improved patient tolerability. Unlike CBZ, it is metabolised by reduction and may not induce hepatic monooxygenase enzymes. 2. Serum concentrations of OXC and its active metabolite 10-OH-carbazepine (10-OH-CZ) were followed after a single 300 mg dose and during and after 300 mg OXC twice daily for 29 doses in eight healthy male volunteers. 3. Antipyrine metabolism, urinary 6-beta-hydroxycortisol excretion, sex hormone binding globulin (SHBG) levels and circulating androgens were measured as indices of hepatic enzyme induction before, during and after treatment with OXC. 4. Elimination half-lives (mean +/- s.e. mean) of 10-OH-CZ were unaltered by 2 weeks' therapy with OXC (before 11.3 +/- 1.1 h; after 13.9 +/- 3 h). Trough plasma concentrations of 10-OH-CZ at steady-state (31 +/- 2.2 mumol l-1) were higher than predicted (16.5 +/- 4 mumol l-1). 5. Antipyrine metabolism, urinary 6-beta-hydroxycortisol excretion, SHBG levels and circulating androgens were unaltered by treatment with OXC. 6. OXC (600 mg daily) does not induce hepatic monooxygenase enzymes and so is likely to have more predictable dose-concentration relationships and to produce fewer physiological and pharmacological interactions than CBZ.
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Affiliation(s)
- J G Larkin
- Epilepsy Research Unit, University Department of Medicine and Therapeutics, Western Infirmary, Glasgow
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29
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el Sheikh HA, Ali BH, Homeida AM, Hapke HJ. Activities of glutathione-S-transferase and ethoxycoumarin-O-deethylase in tissues of camels, sheep, goats and rats. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. C, COMPARATIVE PHARMACOLOGY AND TOXICOLOGY 1991; 98:293-7. [PMID: 1676944 DOI: 10.1016/0742-8413(91)90208-b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
1. The activities of the drug metabolizing enzymes ethoxycoumarin-O-deethylase, glutathione-S-transferase, and protein concentrations were measured in vitro in the liver, kidney and duodenal mucosa of camels, sheep, goats and rats. 2. Enzyme activities were generally higher in the liver than in the kidney and duodenal mucosa in the four species studied. 3. The activities of ethoxycoumarin-O-deethylase and glutathione-S-transferase in liver of male kids were about one third and half of that in adult male goats, respectively. In the kidney and duodenal mucosa of male kids, the activity of glutathione-S-transferase was about 70% and 53% of that in the mature male goat, respectively. In the latter tissues, however, there was no detectable activity of ethoxycoumarin-O-deethylase. 4. In general, goats and sheep had similar activities of the two enzymes which were significantly higher than those found in camels and rats. 5. Some sex-related differences were noted in the activity of the two enzymes studied. Female sheep had significantly higher hepatic glutathione-S-transferase than the male: while the enzyme activity in the kidney and duodenal mucosa of male goats was significantly higher than in females. Male rats had higher hepatic ethoxycoumarin-O-deethylase activity than females.
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Affiliation(s)
- H A el Sheikh
- Department of Veterinary Medicine, Pharmacology and Toxicology, University of Khartoum, F.R. Germany
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30
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Narang AP, Kaur U, Bambery P. Drug metabolism and liver disease in India. Drug Metab Rev 1991; 23:65-81. [PMID: 1868778 DOI: 10.3109/03602539109029756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- A P Narang
- Department of Hepatology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
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31
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Patsalos PN, Zakrzewska JM, Elyas AA. Dose dependent enzyme induction by oxcarbazepine? Eur J Clin Pharmacol 1990; 39:187-8. [PMID: 2253672 DOI: 10.1007/bf00280057] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Antipyrine half life and clearance was compared in four patients with classical idiopathic trigeminal neuralgia during carbamazepine (CBZ) or CBZ/phenytoin (PHT) and after substitution with oxcarbazepine (OXC) monotherapy. OXC is observed to be less of a hepatic enzyme inducer than CBZ or CBZ/PHT in combination, however induction by OXC may be dose related.
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Affiliation(s)
- P N Patsalos
- Institute of Neurology, National Hospital for Nervous Diseases, London, UK
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Loft S, Poulsen HE. Prediction of xenobiotic metabolism by non-invasive methods. PHARMACOLOGY & TOXICOLOGY 1990; 67:101-8. [PMID: 2123982 DOI: 10.1111/j.1600-0773.1990.tb00793.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- S Loft
- Department of Pharmacology, University of Copenhagen, Denmark
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Loft S. Metronidazole and antipyrine as probes for the study of foreign compound metabolism. PHARMACOLOGY & TOXICOLOGY 1990; 66 Suppl 6:1-31. [PMID: 2184425 DOI: 10.1111/j.1600-0773.1990.tb01611.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The aim of the present work was to develop a tool for the study of the enzyme activities relevant for the biotransformation of foreign compounds, their elimination and/or activation to toxic substances. The activity of an enzyme may be assessed by the rate of metabolism of a preferably specific probe or model compound. The cytochrome P450'ies, the key enzymes for the elimination and/or activation of most foreign compounds, exist in multiple forms with variable substrate specificity and regulation. Some cytochrome P450'ies are under genetic control, whereas the activity of others is mainly regulated by the influence from factors in the environment. Only some of the cytochrome P450'ies are relevant for the formation of harmful metabolites. Thus, the activity of as many cytochrome P450 forms as possible should be assessable, preferably simultaneously. The present work evaluated metronidazole in a cocktail with antipyrine as a tool for the study of the regulation of foreign compound metabolism in the liver. The cytochrome P450 catalyzed metabolism of metronidazole and antipyrine was studied in humans and in isolated rat hepatocytes. In humans the influence of dose, route of administration, enzyme induction and inhibition and liver disease was investigated. Rats of either sex were studied with and without pretreatment with specific enzyme inducers and incubations included specific enzyme inhibitors. Evidence was provided that the oxidative formation of the five major metabolites, two from metronidazole and three from antipyrine, depends on different cytochrome P450'ies. In humans it was demonstrated that the clearance of metronidazole and antipyrine could be determined from the same saliva sample collected 16-24 hours after their oral administration and so could the clearance for formation of each metabolite if urine was collected for 48 hours. Thus, with the cocktail of metronidazole and antipyrine and simple non-invasive sampling the activity of five different cytochrome P450'ies can be assessed in vivo. In addition, metronidazole may also be used for assessment of the glucuronidation capacity although this is a minor pathway in man. Because the variation within subjects is much less than between them, the cocktail test is particularly suited for paired designs with measurements before and after an environmental change and the subjects serving as their own control. The metronidazole/antipyrine cocktail may have many applications in the study of the regulation of foreign compound metabolism in man and in animals, in vivo and in vitro.
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Ged C, Rouillon JM, Pichard L, Combalbert J, Bressot N, Bories P, Michel H, Beaune P, Maurel P. The increase in urinary excretion of 6 beta-hydroxycortisol as a marker of human hepatic cytochrome P450IIIA induction. Br J Clin Pharmacol 1989; 28:373-87. [PMID: 2590599 PMCID: PMC1379986 DOI: 10.1111/j.1365-2125.1989.tb03516.x] [Citation(s) in RCA: 239] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
1. Urinary excretion of 6 beta-hydroxycortisol, hepatic microsomal cortisol 6 beta-hydroxylase and the specific content of several forms of cytochrome P450 were measured in 8 to 14 patients before and after treatment with rifampicin (600 mg orally per day for 4 days). 2. Rifampicin treatment produced an average five fold increase in daily excretion of urinary 6 beta-hydroxycortisol. 3. Cortisol 6 beta-hydroxylase activity increased from 15 +/- 6 pmol min-1 mg-1 in organ donors (considered as 'control subjects') to 87 +/- 31 pmol min-1 mg-1 in rifampicin treated patients. 4. Among three forms of human P450 (P450IA, IIC and IIIA), (1), (2), measured by Western blots, only P450IIIA was significantly induced by the antibiotic. 5. Only antibodies against P450IIIA selectively inhibited cortisol 6 beta-hydroxylase in human liver microsomes. 6. Cortisol 6 beta-hydroxylase was correlated with P450IIIA specific content. 7. The urinary level of 6 beta-hydroxycortisol correlated with liver microsomal cortisol 6 beta-hydroxylase and P450IIIA specific content. 8. We conclude that P450IIIA is predominantly responsible for cortisol 6 beta-hydroxylase activity in human liver microsomes and that urinary 6 beta-hydroxycortisol is a marker of the induction of this cytochrome P450.
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Affiliation(s)
- C Ged
- INSERM U 75, Hôpital Necker-Enfants Malades, Paris, France
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Abstract
The microsomal mixed function oxidase system contains the cytochrome P-450 oxidative drug metabolizing family of enzymes. The catalytic cycle of cytochrome P-450 is believed to involve the formation of an active iron-oxygen species which is responsible for oxygen transfer to the substrate. This assumption is supported by the fact that a number of peroxidative agents can replace NADPH, the reductase, and oxygen as co-reactants in most oxidative reactions of microsomal cytochrome P-450. We have found that a mixture of either ferrous or ferric ions with hydrogen peroxide (Fenton and Ruff reagents) can serve as biomimetic models for cytochrome P-450 in hydroxylation, exposidation, sulfoxidation, and N-demethylation of various drugs. The existance of an iron-oxo active species in both Fenton and Ruff type reactions has been postulated and provides reaction cycles similar to those of cytochrome p-450. Other model systems for the hepatic hydroxylation and epoxidation using transition metal complexes with porphyrin are also discussed. The present paper reviews the various biomimetic models of the heme cytochrome P-450 and emphasizes their simulation of hepatic drug metabolism and their potential medical and industrial applications.
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Affiliation(s)
- S Zbaida
- Department of Pharmacy, School of Pharmacy, Hebrew University of Jerusalem, Israel
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36
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Hague RV, May W, Cullen DR. Hepatic microsomal enzyme induction and adrenal crisis due to o,p'DDD therapy for metastatic adrenocortical carcinoma. Clin Endocrinol (Oxf) 1989; 31:51-7. [PMID: 2574647 DOI: 10.1111/j.1365-2265.1989.tb00453.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Two cases are described in which metastatic adrenocortical carcinoma associated with Cushing's syndrome was treated with mitotane (o,p'DDD). The first patient had initially been treated by bilateral adrenalectomy and, whilst responding to mitotane biochemically and by remission of metastases, experienced repeated episodes of adrenal crisis requiring a substantial increase in steroid therapy. The second patient failed to respond to the drug, but evidence of hepatic enzyme induction was noted during its administration. It is suggested that hepatic microsomal enzyme induction can occur in association with treatment with mitotane and that this can lead to an increased destruction of exogenous steroid with clinical consequences.
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Affiliation(s)
- R V Hague
- Department of Medicine, District General Hospital, Barnsley, UK
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Abstract
1. The study was designed to determine the mechanism by which vigabatrin causes a fall in plasma phenytoin concentrations when added to the drug therapy of eight epileptic patients. 2. Total plasma phenytoin concentration was measured before and at intervals during 5 weeks' treatment with vigabatrin. 3. Plasma protein binding of phenytoin, the urinary ratio of phenytoin to 5-(p-hydroxyphenyl)-5-phenylhydantoin, and antipyrine clearance were measured before and at the end of treatment period. 4. Mean plasma phenytoin concentration fell significantly by 23% during the fifth week. 5. No change was found in any of the other measures. 6. Although an interaction between phenytoin and vigabatrin has been confirmed, the mechanism has not been elucidated.
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Affiliation(s)
- E M Rimmer
- Department of Pharmacology and Therapeutics, University of Wales College of Medicine, Heath Park, Cardiff
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38
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Affiliation(s)
- C W Howden
- University Department of Materia Medica, Stobhill General Hospital, Glasgow, Scotland, U.K
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Larkin JG, Macphee GJ, Beastall GH, Brodie MJ. Thyroid hormone concentrations in epileptic patients. Eur J Clin Pharmacol 1989; 36:213-6. [PMID: 2501100 DOI: 10.1007/bf00558149] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Anticonvulsants are associated with decreased serum thyroid hormone concentrations. We have studied thyroid function in 54 epileptic patients on a variety of drugs (19 on carbamazepine, 13 on phenytoin, 10 on sodium valproate, 12 on polypharmacy). For comparison, 14 untreated epileptics and 11 healthy unmedicated volunteers were included as controls. Total thyroxine (T4) concentrations were reduced in patients taking enzyme-inducing drugs (carbamazepine and/or phenytoin) compared with both controls and patients taking sodium valproate. Similar differences were shown with each individual drug. All nine patients whose circulating T4 was below the lower limit of the reference range were taking enzyme inducers. Free thyroxine concentrations were also reduced in individuals treated with carbamazepine and phenytoin with five values falling beneath the reference range. Tri-iodothyronine and thyrotropin appeared unaffected by anticonvulsant administration. Thyrotropin releasing hormone stimulation revealed no true hypothyroidism. The lowering effect of anticonvulsant drugs on circulating total and free T4 was not exhibited by the non-inducing sodium valproate. These data support the influence of enzyme induction as a likely mechanism for reduced thyroxine concentrations in treated epileptic patients.
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Affiliation(s)
- J G Larkin
- University Department of Medicine, Western Infirmary, Glasgow, Scotland, UK
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40
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Tanaka E, Nakamura K. Comparison of trimethadione and antipyrine as indicators of oxidative drug metabolizing capacity in man. Eur J Clin Pharmacol 1989; 36:629-32. [PMID: 2776822 DOI: 10.1007/bf00637749] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Ten healthy male volunteers were given trimethadione (TMO) 4 mg/kg and antipyrine (AP) 500 mg alone or concomitantly to determine whether the metabolism of the drugs was mediated by the same or closely related forms of cytochrome P-450. Whether administered alone or together the clearance (CL) and half-life (t 1/2) of TMO and AP were the same, and there was a good correlation between the CL and t 1/2 of TMO and AP (alone r = 0.755 and 0.623, respectively; coadministered r = 0.771 and 0.503, respectively). Excretion of AP and its main metabolite and the clearance for production of AP metabolites after AP was administered alone were not significantly different when TMO and AP were taken together. When the two drugs were administered alone or coadministered, the correlation between the CL of TMO and the excretion of 3-hydroxymethyl-3-norantipyrine (NORA) was close (alone r = 0.734, coadministered r = 0.749). The correlation between the CL of TMO and CLm of NORA when TMO and AP were given alone or concomitantly was 0.762 and 0.772, respectively. The findings suggest that TMO metabolism and the formation of NORA in healthy subjects are mediated by a closely related form(s) of the cytochrome P-450 system.
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Affiliation(s)
- E Tanaka
- Institute of Community Medicine, University of Tsukuba, Japan
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41
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42
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Schellens JH, van der Wart JH, Danhof M, van der Velde EA, Breimer DD. Relationship between the metabolism of antipyrine, hexobarbitone and theophylline in man as assessed by a 'cocktail' approach. Br J Clin Pharmacol 1988; 26:373-84. [PMID: 3190987 PMCID: PMC1386557 DOI: 10.1111/j.1365-2125.1988.tb03394.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
1. Three model substrates for the characterization of drug oxidation activity, antipyrine (AP), hexobarbitone (HB) and theophylline (TH), were administered to 26 healthy volunteers on two different occasions: in the first experiment a combination of AP (250 mg) and HB (250 mg) was given and in the second experiment TH (150 mg) was added to the former combination. 2. Plasma concentrations of AP, HB and TH and urinary excretion of TH and the three main metabolites of AP (3-hydroxymethylantipyrine: HMA, norantipyrine: NORA and 4-hydroxyantipyrine: OHA) were determined and the intrinsic clearance (CLint) of the three substrates and the clearance to the formation of AP metabolites were calculated. 3. The correlation coefficients between CLHB and CL-greater than metabolites of AP were highest for CL-greater than HMA and CL-greater than NORA (greater than 0.80) and lowest for CL-greater than OHA (0.63). High correlation coefficients also were found between CLTH and CL-greater than OHA (0.89) and CL-greater than HMA (0.80). 4. Ideal relationships, defined by a slope of the orthogonal regression line equal to unity, did exist between CLHB and CL-greater than HMA as well as CL-greater than NORA and between CLTH and CLAP as well as CL-greater than OHA. 5. Based on the results of correlation and regression analysis it can be concluded that isozymes of the cytochrome P-450 system responsible for the oxidation of HB and formation of HMA and NORA are very closely related and also that isozymes responsible for the oxidation of TH and formation of OHA show a very close relation. 6. With this strategy of simultaneous administration of substrates ('cocktail' approach) it seems possible to characterize and correlate activities of different P-450 isozymes and to investigate their in vivo substrate selectivity without the disturbing influence of intra-individual variation in drug oxidation.
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Affiliation(s)
- J H Schellens
- Center for Bio-Pharmaceutical Sciences, Division of Pharmacology, Leiden, The Netherlands
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43
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Philip PA, Lewis LD, James CA, Rogers HJ. Ifosfamide plasma clearance in relation to polymorphic debrisoquine oxidation. Cancer Chemother Pharmacol 1988; 22:321-4. [PMID: 3168145 DOI: 10.1007/bf00254239] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Ifosfamide (IF) pharmacokinetics and the plasma (NBP)-alkylating activity were determined in 33 patients with different tumours after the administration of IF as single-agent chemotherapy. All subjects had been phenotyped for debrisoquine oxidation. There is a lack of correlation between the debrisoquine metabolic ratio (DMR) and either the total plasma clearance of IF (CLIF) or the AUC of the plasma NBP-alkylating activity.
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Affiliation(s)
- P A Philip
- Department of Clinical Pharmacology, United Medical School, Guy's Hospital, London Bridge, U.K
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44
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Patsalos PN, Duncan JS, Shorvon SD. Effect of the removal of individual antiepileptic drugs on antipyrine kinetics, in patients taking polytherapy. Br J Clin Pharmacol 1988; 26:253-9. [PMID: 3179165 PMCID: PMC1386536 DOI: 10.1111/j.1365-2125.1988.tb05274.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
1. Antipyrine (AP) clearance, half-life and volume of distribution were determined in 52 patients, taking one or more antiepileptic drug (AED), before and 4 weeks after the complete removal of phenytoin (PHT, n = 20), carbamazepine (CBZ, n = 15) and sodium valproate (VPA, n = 17). 2. PHT removal was associated with a mean 13% fall in AP clearance and a mean 16% increase in AP half-life, in patients who were also taking CBZ with or without barbiturates. There was no significant difference between patients who did, and did not, take barbiturates, in addition to CBZ. 3. CBZ removal was associated with a mean 45% fall in AP clearance and a mean 69% increase in AP half-life, if there was no inducing AED comedication, but had no effect on AP clearance and half-life if PHT and/or barbiturates were also being taken. 4. Removal of VPA had no effect on AP clearance or half-life. 5. The removal of PHT, CBZ and VPA had no significant effect on AP volume of distribution. 6. PHT appears to be a more powerful inducer of hepatic enzyme activity, as measured by the AP test, than is CBZ.
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Affiliation(s)
- P N Patsalos
- Institute of Neurology, National Hospital for Nervous Diseases, Queen Square, London
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45
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Back DJ, Tjia J, Mönig H, Ohnhaus EE, Park BK. Selective inhibition of drug oxidation after simultaneous administration of two probe drugs, antipyrine and tolbutamide. Eur J Clin Pharmacol 1988; 34:157-63. [PMID: 3383988 DOI: 10.1007/bf00614553] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The effects of sulphaphenazole, cimetidine and primaquine on the disposition of antipyrine and tolbutamide in healthy volunteers have been investigated. The model substrates were administered simultaneously in order more clearly to define any selective effects of the potential inhibitors. Sulphaphenazole produced a significant increase in the half-life of tolbutamide (7.10 to 21.50 h) and a corresponding decrease in its clearance (0.260 to 0.084 ml.min-1.kg-1). Clearance to hydroxytolbutamide (OHTOL) and carboxytolbutamide (COOHTOL) was also significantly decreased. In contrast, sulphaphenazole had no effect on the disposition of antipyrine. Administration of cimetidine did not significantly alter the disposition of either model drug. However, a 1.6-times higher dose of cimetidine did increase the half lives both of tolbutamide and antipyrine (6.21 to 9.04 h and 14.2 to 19.2 h, respectively) and decrease their clearance (0.226 to 0.148 and 0.50 to 0.31 ml.min-1 kg-1, respectively). Clearance to OHTOL and hydroxymethylantipyrine (HMA) was reduced. A single dose of primaquine had no demonstrable effect on tolbutamide disposition whereas the half-life of antipyrine was increased (12.1 to 15.0 h) and its clearance decreased (0.63 to 0.38 ml.min-1.kg-1). The partial clearance to HMA, 4-hydroxyantipyrine (OHA) and norantipyrine (NORA) was also significantly reduced. The two main inferences are first, that tolbutamide and antipyrine are metabolised by different forms of cytochrome P-450, and second that a battery of model substrates is needed to investigate the inhibitory effects of a drug in man.
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Affiliation(s)
- D J Back
- Department of Pharmacology and Therapeutics, University of Liverpool, England
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el Sheikh HA, Ali BH, Homeida AM, Hassan T, Hapke HJ. The activities of aminopyrine N-demethylase, aniline 4-hydroxylase and UDP-glucuronyltransferase in tissues of camels, desert sheep and Nubian goats. GENERAL PHARMACOLOGY 1988; 19:713-7. [PMID: 3145901 DOI: 10.1016/0306-3623(88)90134-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
1. The activities of the drug-metabolizing enzymes, aminopyrine N-demethylase, aniline 4-hydroxylase and UDP-glucuronyltransferase have been measured in vitro in the liver, kidney and duodenal mucosa of camels, sheep, goats and rats. 2. Enzyme activities were generally higher in the liver, followed by the duodenal mucosa, then the kidney in all species. 3. Male kids had much lower enzyme activity in the liver when compared to adult goats, and in the former animal, no measurable activity could be detected in the duodenal mucosa or kidney. 4. In general, goats seemed to have the highest and camels the lowest enzyme activity when compared to the other species. 5. Some sex differences were noted in the three enzymes studied. In sheep duodenal mucosa and rat liver and duodenal mucosa, males had higher aminopyrine N-demethylase than females. In rat liver and goat duodenal mucosa males had higher aniline 4-hydroxylase than females. Male rats had higher UDP-glucuronyltransferase in liver when compared to females.
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Affiliation(s)
- H A el Sheikh
- Department of Veterinary Medicine, Pharmacology and Toxicology, University of Khartoum, Sudan
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47
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van der Graaff M, Vermeulen NP, Breimer DD. Disposition of hexobarbital: 15 years of an intriguing model substrate. Drug Metab Rev 1988; 19:109-64. [PMID: 3069420 DOI: 10.3109/03602538809049621] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- M van der Graaff
- Department of Pharmaceutics, Organon International B.V., Oss, The Netherlands
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48
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Carlson GP, Chadwick RW. Comparability of in vitro and in vivo methods for the determination of alterations in drug metabolism. Toxicol Lett 1987; 39:125-38. [PMID: 2446403 DOI: 10.1016/0378-4274(87)90225-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The above series of experiments taken in toto suggest the usefulness of lindane as a model substrate for studying the effects of a variety of compounds on drug metabolism in vivo. Excellent correlations were observed in comparison with the in vitro measurements both qualitatively and quantitatively. Unlike some of the other compounds discussed lindane offers some distinct advantages. One is that because the metabolites can be monitored in the urine, it is non-invasive in nature. A second is that a number of mixed function oxidase pathways (phase I reactions) can be determined at the same time. This would be of great importance if the effect of a compound is rather selective and does not alter the single pathway measured in the metabolism of other substrates which have been suggested as model compounds. However, the tradeoff is obviously the need for more analytical work. A third advantage is the ability of the system to detect changes in conjugative or phase II reactions at the same time. Further studies will be necessary with all of these model substrates to detect their usefulness and their limitations.
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Affiliation(s)
- G P Carlson
- Department of Pharmacology and Toxicology, School of Pharmacy and Pharmacal Sciences, Purdue University, West Lafayette, IN 47907
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49
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Fonne-Pfister R, Bargetzi MJ, Meyer UA. MPTP, the neurotoxin inducing Parkinson's disease, is a potent competitive inhibitor of human and rat cytochrome P450 isozymes (P450bufI, P450db1) catalyzing debrisoquine 4-hydroxylation. Biochem Biophys Res Commun 1987; 148:1144-50. [PMID: 3500719 DOI: 10.1016/s0006-291x(87)80252-8] [Citation(s) in RCA: 112] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
In human liver microsomal preparations the neurotoxic chemical N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and several of its analogs competitively inhibited bufuralol 1'-hydroxylase activity of cytochrome P450bufI. This enzyme is the target of the common genetic polymorphism of drug oxidation known as debrisoquine polymorphism. Bufuralol 1'-hydroxylase activity was detectable in rat brain tissue. The activity was inhibited by antisera raised against a rat liver cytochrome P450 called P450db1. Immunoblotting experiments revealed the presence of a protein in rat and human brain microsomes with the same electrophoretic properties as the liver enzyme. These data suggest that P450bufI may be involved in the metabolism and neurotoxicity of MPTP.
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Affiliation(s)
- R Fonne-Pfister
- Department of Pharmacology, University of Basel, Switzerland
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50
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Burgess P, Hall RI, Bateman DN, Johnston ID. The effect of total parenteral nutrition on hepatic drug oxidation. JPEN J Parenter Enteral Nutr 1987; 11:540-3. [PMID: 3123723 DOI: 10.1177/0148607187011006540] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Hepatic dysfunction is a frequent complication of total parenteral nutrition (TPN), indicated by derangement of standard liver function tests. However, such changes are variable and nonspecific, and represent hepatic injury rather than changes in hepatic function. Antipyrine (Phenazone) clearance is a sensitive indicator of hepatic microsomal enzyme activity and provides a more specific indication of hepatic function. This was used to investigate the effect of different TPN regimens. Patients receiving a postoperative 2000 kcal TPN regimen providing all nonprotein calories as dextrose (n = 16) showed a 34% reduction of mean antipyrine clearance after 7 days of TPN compared to controls (n = 13, p less than 0.05). This effect was seen also in patients receiving a 1600 kcal dextrose-based regimen (n = 8). In patients receiving a 2000 kcal TPN regimen in which 500 kcal were provided as lipid (n = 10), mean antipyrine clearance was not significantly different from that of the control group. This study indicates the sensitivity of hepatic microsomal oxidative function, an important route of drug metabolism, to different TPN regimens.
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Affiliation(s)
- P Burgess
- Department of Surgery, Medical School, Newcastle upon Tyne, England
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