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Pilton JL, Chau J, Foo TS, Hall EJ, Martinez-Taboada F, Podadera JM, Makara MA. Hepatic computed tomography and cholangiography by use of gadoxetic acid in healthy cats. Am J Vet Res 2019; 80:385-395. [PMID: 30919679 DOI: 10.2460/ajvr.80.4.385] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To evaluate 3 doses of gadoxetic acid (Gd-EOB-DPTA) for hepatic CT and cholangiography in cats and to determine optimal timing for hepatobiliary image acquisition and evaluation of the contrast-enhanced hepatobiliary anatomy. ANIMALS 6 healthy cats. PROCEDURES Cats were anesthetized; sequential CT scans were performed 0, 5, 25, 45, 65, and 85 minutes after IV administration of Gd-EOB-DTPA at low (0.0125 mmol/kg), medium (0.1 mmol/kg), and high (0.3 mmol/kg) doses. Hepatobiliary enhancement for each dose was objectively assessed over time and by use of a subjective semiquantitative visual assessment score. RESULTS No contrast-related adverse effects were detected. Each increase in dose of contrast medium resulted in a significant increase in HU across the hepatobiliary system. The liver had a significantly higher number of HU at 45 minutes, with homogenous enhancement at all doses of contrast medium. Contrast-enhanced cystic and bile duct HU were significantly higher and maximal at 65 minutes. Contrast-enhanced gallbladder HU did not plateau by 85 minutes. At a high dose of contrast medium, 12 of 60 (20%) biliary tract scores indicated no enhancement, 34 (57%) indicated poor enhancement, and 14 (23%) indicated moderate enhancement. No cat had excellent enhancement of the biliary tract at any dose. CONCLUSIONS AND CLINICAL RELEVANCE Gd-EOB-DTPA-enhanced hepatic CT and cholangiography in cats were safely performed and provided good hepatic enhancement but poor to moderate enhancement of the biliary tract. This technique may be useful for assessing the liver parenchyma in cats, but its value for assessing the biliary tract is questionable.
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Saengtienchai A, Ikenaka Y, Kawata M, Kawai Y, Takeda K, Kondo M, Bortey-Sam N, Nakayama SMM, Mizukawa H, Ishizuka M. Comparison of xenobiotic metabolism in phase I oxidation and phase II conjugation between rats and bird species. Comp Biochem Physiol C Toxicol Pharmacol 2018; 214:28-35. [PMID: 30176376 DOI: 10.1016/j.cbpc.2018.08.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 03/14/2018] [Accepted: 08/28/2018] [Indexed: 02/01/2023]
Abstract
There have been many reports regarding toxic chemicals in birds. Chemicals are mainly metabolized in the liver through phase I oxidation by cytochrome P450 (CYP) and phase II conjugation by conjugated enzymes, such as UDP-glucuronosyltransferase (UGT), sulfotransferase (SULT), glutathione-S-transferase (GST), etc. Xenobiotic metabolism differs among bird species, but little detailed information is available. In the present study, the four-ring polycyclic aromatic hydrocarbon (PAH), pyrene, was used as a model xenobiotic to clarify the characteristics of xenobiotic metabolism in birds compared with laboratory animals by in vivo and in vitro studies. Plasma, bile, and excreta (urine and feces) were collected after oral administration of pyrene and analyzed to clarify xenobiotic metabolism ability in chickens and quails. Interestingly, pyrenediol-glucuronide sulfate (PYDOGS) and pyrenediol-diglucuronide (PYDOGG) were present in chickens and quails but not in rats. In addition, the area under the curve (AUC), maximum plasma concentration (Cmax), and time to maximum plasma concentration (Tmax) of pyrene-1-sulfate (PYOS) were higher than those of the parent molecule, pyrene, while the elimination half-life (t1/2) and mean residence time (MRT) were faster than those of the parent pyrene. With regard to sulfation of 1-hydroxypyrene (PYOH), the maximum velocity (Vmax) and Michaelis constant (Km) of rat liver cytosol were greater than those of chicken and quail liver cytosol. Furthermore, Vmax/Km of UGT activity in rat liver microsomes was also greater than those of chicken and quail liver microsomes. Characterization of xenobiotic metabolism revealed species differences between birds and mammals, raising concerns about exposure to various xenobiotics in the environment.
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Affiliation(s)
- Aksorn Saengtienchai
- Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, N18 W9, Kita-ku, Sapporo 060-0818, Japan; Department of Pharmacology, Faculty of Veterinary Medicine, Kasetsart University, 50 Ngam Wong Wan Rd, Lat Yao, Chatuchak, Bangkok 10900, Thailand
| | - Yoshinori Ikenaka
- Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, N18 W9, Kita-ku, Sapporo 060-0818, Japan; Water Research Group, Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa.
| | - Minami Kawata
- Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, N18 W9, Kita-ku, Sapporo 060-0818, Japan
| | - Yusuke Kawai
- Department of Animal and Food Hygiene, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan
| | - Kazuki Takeda
- Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, N18 W9, Kita-ku, Sapporo 060-0818, Japan
| | - Mitsuki Kondo
- Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, N18 W9, Kita-ku, Sapporo 060-0818, Japan
| | - Nesta Bortey-Sam
- Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, N18 W9, Kita-ku, Sapporo 060-0818, Japan
| | - Shouta M M Nakayama
- Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, N18 W9, Kita-ku, Sapporo 060-0818, Japan
| | - Hazuki Mizukawa
- Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, N18 W9, Kita-ku, Sapporo 060-0818, Japan
| | - Mayumi Ishizuka
- Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, N18 W9, Kita-ku, Sapporo 060-0818, Japan
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Malik MY, Jaiswal S, Sharma A, Shukla M, Lal J. Role of enterohepatic recirculation in drug disposition: cooperation and complications. Drug Metab Rev 2016; 48:281-327. [PMID: 26987379 DOI: 10.3109/03602532.2016.1157600] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Enterohepatic recirculation (EHC) concerns many physiological processes and notably affects pharmacokinetic parameters such as plasma half-life and AUC as well as estimates of bioavailability of drugs. Also, EHC plays a detrimental role as the compounds/drugs are allowed to recycle. An in-depth comprehension of this phenomenon and its consequences on the pharmacological effects of affected drugs is important and decisive in the design and development of new candidate drugs. EHC of a compound/drug occurs by biliary excretion and intestinal reabsorption, sometimes with hepatic conjugation and intestinal deconjugation. EHC leads to prolonged elimination half-life of the drugs, altered pharmacokinetics and pharmacodynamics. Study of the EHC of any drug is complicated due to unavailability of the apposite model, sophisticated procedures and ethical concerns. Different in vitro and in vivo methods for studies in experimental animals and humans have been devised, each having its own merits and demerits. Involvement of the different transporters in biliary excretion, intra- and inter-species, pathological and biochemical variabilities obscure the study of the phenomenon. Modeling of drugs undergoing EHC has always been intricate and exigent models have been exploited to interpret the pharmacokinetic profiles of drugs witnessing multiple peaks due to EHC. Here, we critically appraise the mechanisms of bile formation, factors affecting biliary drug elimination, methods to estimate biliary excretion of drugs, EHC, multiple peak phenomenon and its modeling.
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Affiliation(s)
- Mohd Yaseen Malik
- a Department of Pharmaceutics , National Institute of Pharmaceutical Education and Research (NIPER) , Raebareli , India ;,b Pharmacokinetics & Metabolism Division , CSIR-Central Drug Research Institute , Lucknow , India
| | - Swati Jaiswal
- b Pharmacokinetics & Metabolism Division , CSIR-Central Drug Research Institute , Lucknow , India ;,c Academy of Scientific and Innovative Research , New Delhi , India
| | - Abhisheak Sharma
- b Pharmacokinetics & Metabolism Division , CSIR-Central Drug Research Institute , Lucknow , India ;,c Academy of Scientific and Innovative Research , New Delhi , India ;,d Department of Pharmaceutics and Drug Delivery, School of Pharmacy , The University of Mississippi , Oxford , USA
| | - Mahendra Shukla
- b Pharmacokinetics & Metabolism Division , CSIR-Central Drug Research Institute , Lucknow , India ;,c Academy of Scientific and Innovative Research , New Delhi , India
| | - Jawahar Lal
- b Pharmacokinetics & Metabolism Division , CSIR-Central Drug Research Institute , Lucknow , India ;,c Academy of Scientific and Innovative Research , New Delhi , India
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Cherkas Y, McMillian MK, Amaratunga D, Raghavan N, Sasaki JC. ABC gene-ranking for prediction of drug-induced cholestasis in rats. Toxicol Rep 2016; 3:252-261. [PMID: 28959545 PMCID: PMC5615833 DOI: 10.1016/j.toxrep.2016.01.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 01/02/2016] [Accepted: 01/12/2016] [Indexed: 12/22/2022] Open
Abstract
As legacy toxicogenomics databases have become available, improved data mining approaches are now key to extracting and visualizing subtle relationships between toxicants and gene expression. In the present study, a novel “aggregating bundles of clusters” (ABC) procedure was applied to separate cholestatic from non-cholestatic drugs and model toxicants in the Johnson & Johnson (Janssen) rat liver toxicogenomics database [3]. Drug-induced cholestasis is an important issue, particularly when a new compound enters the market with this liability, with standard preclinical models often mispredicting this toxicity. Three well-characterized cholestasis-responsive genes (Cyp7a1, Mrp3 and Bsep) were chosen from a previous in-house Janssen gene expression signature; these three genes show differing, non-redundant responses across the 90+ paradigm compounds in our database. Using the ABC procedure, extraneous contributions were minimized in comparisons of compound gene responses. All genes were assigned weights proportional to their correlations with Cyp7a1, Mrp3 and Bsep, and a resampling technique was used to derive a stable measure of compound similarity. The compounds that were known to be associated with rat cholestasis generally had small values of this measure relative to each other but also had large values of this measure relative to non-cholestatic compounds. Visualization of the data with the ABC-derived signature showed a very tight, essentially identically behaving cluster of robust human cholestatic drugs and experimental cholestatic toxicants (ethinyl estradiol, LPS, ANIT and methylene dianiline, disulfiram, naltrexone, methapyrilene, phenacetin, alpha-methyl dopa, flutamide, the NSAIDs–—indomethacin, flurbiprofen, diclofenac, flufenamic acid, sulindac, and nimesulide, butylated hydroxytoluene, piperonyl butoxide, and bromobenzene), some slightly less active compounds (3′-acetamidofluorene, amsacrine, hydralazine, tannic acid), some drugs that behaved very differently, and were distinct from both non-cholestatic and cholestatic drugs (ketoconazole, dipyridamole, cyproheptadine and aniline), and many postulated human cholestatic drugs that in rat showed no evidence of cholestasis (chlorpromazine, erythromycin, niacin, captopril, dapsone, rifampicin, glibenclamide, simvastatin, furosemide, tamoxifen, and sulfamethoxazole). Most of these latter drugs were noted previously by other groups as showing cholestasis only in humans. The results of this work suggest that the ABC procedure and similar statistical approaches can be instrumental in combining data to compare toxicants across toxicogenomics databases, extract similarities among responses and reduce unexplained data varation.
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Affiliation(s)
| | | | | | - Nandini Raghavan
- Janssen Research and Development, LLC, Titusville, NJ 08540, USA
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Efficacy and pharmacokinetics of OZ78 and MT04 against a natural infection with Fasciola hepatica in sheep. Vet Parasitol 2013; 198:102-10. [PMID: 24011678 DOI: 10.1016/j.vetpar.2013.08.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 07/31/2013] [Accepted: 08/05/2013] [Indexed: 11/23/2022]
Abstract
Fasciolosis is a parasitosis caused by the food-borne trematode Fasciola spp. of major veterinary significance. Triclabendazole is the first line treatment in humans and animals but cases of resistance are spreading worldwide. The synthetic peroxides OZ78 and MT04 are lead compounds for the treatment of fasciolosis. In the present study we investigated the efficacy and drug disposition following a single intramuscular dose of 100 mg/kg OZ78 and MT04 in sheep harbouring a natural Fasciola hepatica infection. A liquid chromatography and tandem mass spectrometry (LC-MS/MS) method was developed and validated to quantify plasma and bile concentrations of both compounds. Plasma samples were analysed with an accuracy for OZ78 and MT04 from 91 to 115% and a precision lower than 8.9%. Bile samples displayed an accuracy between 92 and 101% and a precision up to 12.7%. Bile samples were collected at 0 and 6h post-administration. Plasma mean peak concentration was 11.1 μg/ml at 1.5 h for OZ78 and 4.8 μg/ml at 4.2 h for MT04. Mean AUC of OZ78 and MT04 was 6698 and 3567 μg min/ml, respectively. Bile concentration at 6h post-treatment was 1.0 μg/ml for OZ78 and 1.4 μg/ml for MT04. Treatment with OZ78 showed no effect on egg burden and adult worm counts in vivo, whereas MT04 displayed a significant egg count reduction of 98.5% and a worm burden reduction of 92%. In conclusion, our study reveals an excellent activity of MT04 against F. hepatica in naturally infected sheep and a first insight into its PK behaviour.
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Morris ME, Yang X, Gandhi YA, Bhansali SG, Benincosa LJ. Interspecies scaling: prediction of human biliary clearance and comparison with QSPKR. Biopharm Drug Dispos 2012; 33:1-14. [DOI: 10.1002/bdd.1761] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 11/15/2011] [Accepted: 11/22/2011] [Indexed: 11/09/2022]
Affiliation(s)
- Marilyn E. Morris
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences; University at Buffalo, State University of New York; Amherst; NY; 14260; USA
| | - Xinning Yang
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences; University at Buffalo, State University of New York; Amherst; NY; 14260; USA
| | - Yash A. Gandhi
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences; University at Buffalo, State University of New York; Amherst; NY; 14260; USA
| | - Suraj G. Bhansali
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences; University at Buffalo, State University of New York; Amherst; NY; 14260; USA
| | - Lisa J. Benincosa
- Drug Metabolism and Pharmacokinetics Development; Hoffmann-La Roche Inc.; Nutley; NJ; USA
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Efficacy, safety and pharmacokinetics of 1,2,4-trioxolane OZ78 against an experimental infection with Fasciola hepatica in sheep. Vet Parasitol 2010; 173:228-35. [DOI: 10.1016/j.vetpar.2010.06.031] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 06/13/2010] [Accepted: 06/21/2010] [Indexed: 11/21/2022]
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Abou-El-Makarem MM, Millburn P, Smith RL. Biliary excretion of [C]succinylsulphathiazole in the rat and rabbit. Biochem J 2010; 105:1295-9. [PMID: 16742559 PMCID: PMC1198454 DOI: 10.1042/bj1051295] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
1. After intravenous injection about 30% of the dose (20mg./kg.) of succinylsulphathiazole is excreted unchanged in the bile in 3hr. by the rat, whereas only about 1% is excreted by the rabbit. When the renal pedicles are ligated the biliary excretion of succinylsulphathiazole in the rat increases to about 80% of the dose, but in the rabbit under these conditions the biliary excretion is only 2% of the dose. 2. In the rat, the sulphonamide readily enters the liver and biliary excretion occurs against a concentration gradient from liver to bile; further, the excretory process can be saturated, and can be depressed by the simultaneous administration of phenolphthalein glucuronide or bile salts. 3. In the rabbit, these conditions have not been found; succinylsulphathiazole does not readily enter the liver from the plasma, there is no transfer of the drug from the liver cells to the bile against a concentration gradient, and no saturation or depression of the biliary excretion of succinylsulphathiazole is found. 4. It is suggested that two factors responsible, at least partly, for the low biliary excretion of succinylsulphathiazole in the rabbit are the poor entry of the sulphonamide into the liver in this species and a deficiency of the concentrative mechanism for its excretion in the bile.
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9
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Biliary excretion in dogs: Evidence for a molecular weight threshold. Eur J Pharm Sci 2010; 40:33-7. [DOI: 10.1016/j.ejps.2010.02.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Accepted: 02/16/2010] [Indexed: 11/19/2022]
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Luo G, Johnson S, Hsueh MM, Zheng J, Cai H, Xin B, Chong S, He K, Harper TW. In silico prediction of biliary excretion of drugs in rats based on physicochemical properties. Drug Metab Dispos 2009; 38:422-30. [PMID: 19995888 DOI: 10.1124/dmd.108.026260] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Evaluating biliary excretion, a major elimination pathway for many compounds, is important in drug discovery. The bile duct-cannulated (BDC) rat model is commonly used to determine the percentage of dose excreted as intact parent into bile. However, a study using BDC rats is time-consuming and cost-ineffective. The present report describes a computational model that has been established to predict biliary excretion of intact parent in rats as a percentage of dose. The model was based on biliary excretion data of 50 Bristol-Myers Squibb Co. compounds with diverse chemical structures. The compounds were given intravenously at <10 mg/kg to BDC rats, and bile was collected for at least 8 h after dosing. Recoveries of intact parents in bile were determined by liquid chromatography with tandem mass spectrometry. Biliary excretion was found to have a fairly good correlation with polar surface area (r = 0.76) and with free energy of aqueous solvation (DeltaG(solv aq)) (r = -0.67). In addition, biliary excretion was also highly corrected with the presence of a carboxylic acid moiety in the test compounds (r = 0.87). An equation to calculate biliary excretion in rats was then established based on physiochemical properties via a multiple linear regression. This model successfully predicted rat biliary excretion for 50 BMS compounds (r = 0.94) and for 25 previously reported compounds (r = 0.86) whose structures are markedly different from those of the 50 BMS compounds. Additional calculations were conducted to verify the reliability of this computation model.
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Affiliation(s)
- Gang Luo
- Pharmaceutical Candidate Optimization-Metabolism and Pharmacokinetics, Bristol-Myers Squibb Company, Pennington, New Jersey 08534, USA
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Alaneme FO, Maduagwu EN. Pharmacokinetics of biliary excretion of N-nitrosodimethylamine in rats fed diets containing levels of protein. Malawi Med J 2004; 16:6-8. [PMID: 27528980 PMCID: PMC3345499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023] Open
Abstract
Albino Wistar rats (Rattus norvegius) fed semi-purified diets containing 3.5%, 8%, 27%, and 64% casein, respectively, as the protein source, were poisoned with an intraperitoneal dose of 20mg N-nitrosodimethylamine (NDMA)/kg, following cannulation of the bile duct, in vitro, under urethane anaesthesia. Bile exudates was collected at designated time intervals and analysed for unchanged NDMA using thin layer chromatography and gas liquid chromatography methods. Rats on 64% high protein diet (HPD) were the highest excretors of NDMA, followed by rats on the 3.5% kwashiorkorigenic diet (KWD), 8% low protein diet (LPD) and 27% normal protein diet (NDP) as the least excretors, in that order. The corresponding values for culmulative excretions of NDMA were 4.38%, 2.74%, 2.96% and 4.11%, and for elimination rate contents they were 54.05Kh(-1), 23.01Kh(-1), 23.76Kh(-1) and 48.88Kh(-1), while the respective elimination half-life values were 0.013h, 0.031h, 0.029h and 0.014h. The toxicological and pharmacological implication of the pharmacokinetic findings are discussed.
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Affiliation(s)
- F O Alaneme
- Department of Biochemistry, College of Medicine, University of Ibadan, Ibadan, Nigeria
| | - E N Maduagwu
- Department of Biochemistry, College of Medicine, University of Ibadan, Ibadan, Nigeria
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Reichl FX, Durner J, Manhart J, Spahl W, Gempel K, Kehe K, Liebl B, Walther UI, Hume WR, Hickel R. Biological clearance of HEMA in guinea pigs. Biomaterials 2002; 23:2135-41. [PMID: 11962654 DOI: 10.1016/s0142-9612(01)00344-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
No toxicokinetic data are available about the dental composite component 2-hydroxyethylmethacrylate (HEMA) in vivo in the literature. Therefore, the excretion of HEMA in feces and urine in vivo and, using the pendular perfusion technique with segments of jejunum and colon, in the biliary and enteric excretion in situ were investigated in anesthetized guinea pigs. In the in situ experiments, guinea pigs (n = 4) received HEMA (0.02 mmol/kgbw labelled with a tracer dose 14C-HEMA 0.3 kBq/gbw) injected into the jugular vein. In the in vivo experiments, guinea pigs (n = 4) received HEMA (+ 14C-HEMA, same dose as above) via gastric tube. Urine and feces were collected for 24h. In the in situ experiments, organs from guinea pigs were removed 60 min after the beginning of the experiment, and then the 14C-radioactivity was measured. During the 60 min perfusion period the calculated amount of 14C-activity excreted into the total jejunum and colon was 6.0 +/- 1.0% and 2.7 +/- 0.7% of the dose administered, respectively (mean +/- sem). Of the 14C-HEMA dose, 5.3 +/- 0.3% was found in the bile. Significantly (p < 0.05) higher bile/blood concentration ratios were found at 10-40 min after the injection of HEMA, as compared to the ratio at 60 min. The total 14C-recovery in all organs tested was 20.0 +/- 2.6%. During 24h the amounts of 14C-activity excreted in the feces and urine were 1.1 +/- 0.1% or 17.1 +/- 1.50% of the dose administered, respectively (mean +/- sem). The total 14C-recovery in all organs tested was 11.6 +/- 0.6%. In a second series of in vivo experiments, exhaled air from the animals was captured during the 24h experimental period. 14C was exhaled to 63.6 +/- 2.11% of the administered 14C-HEMA dose (mean +/- sem; n = 4) as 14C-carbondioxide. The results indicate a rapid clearance of 14C-HEMA and/or 14C-HEMA metabolite(s) from the organism, exhalation being the major route of elimination.
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Affiliation(s)
- F X Reichl
- Walther-Straub-Institute of Pharmacology and Toxicology, Ludwig-Maximilians-University of Munich, Germany.
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Affiliation(s)
- D V Parke
- School of Biological Sciences, University of Surrey, Guildford, UK
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15
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Reichl FX, Kreppel H, Szinicz L, Mückter H, Fichtl B, Forth W. Effect of various antidotes on the biliary and intestinal excretion of arsenic in situ and into the feces in vivo in guinea-pigs after injection of As2O3. Arch Toxicol 1994; 69:35-8. [PMID: 7536408 DOI: 10.1007/s002040050134] [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: 01/25/2023]
Abstract
The effect of various antidotes on the excretion of arsenic into the feces in vivo and on the biliary and enteric excretion in situ was investigated on segments of jejunum and colon in anesthetized guinea-pigs using the pendular perfusion technique, according to Henning and Forth (1982). In the in situ experiments guinea-pigs received As2O3 (0.02 mmol As(III)/kg) and 30 min later, British-Anti-Lewisite (BAL), dimercaptopropanesulfonic acid (DMPS), dimercaptosuccinic acid (DMSA) or 2,3-bis-(acetylthio)propanesulfonamide (BAPSA) (0.1 or 0.7 mmol/kg each) into the jugular vein. In the in vivo experiments guinea-pigs received As2O3 s.c. (same dose as above) and 30 min later the same antidotes (0.1 mmol/kg i.p.). The feces were collected for 24 h and the arsenic content measured. During the 60-min perfusion period the amount of arsenic excreted into the jejunum or colon was only 3% or 0.4% of the dose administered, respectively. Of the arsenic dose, 8% was found in the bile. None of the antidotes had an effect on the arsenic excretion into the jejunum or colon. No change in biliary excretion was found in animals treated with BAL, 0.1 or 0.7 mmol/kg, respectively. DMSA, BAPSA or DMPS, 0.1 mmol/kg, increased the biliary excretion of arsenic to 14, 33, or 43% of the dose administered and after 0.7 mmol/kg to 29, 37, or 42%, respectively. Furthermore, a significant increase (P > 0.05) was found for the bile/blood concentration ratio in the following order: control < BAL < DMSA < BAPSA approximately DMPS.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- F X Reichl
- Walther Straub-Institut für Pharmakologie und Toxikologie, Ludwig-Maximilians-Universität München, Germany
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Role of intestinal transport and first pass liver extraction on oral delivery of renin inhibitor compounds. Int J Pharm 1994. [DOI: 10.1016/0378-5173(94)90053-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Reichl FX, Mückter H, Kreppel H, Forth W. Effect of various antidotes on biliary excretion of arsenic in isolated perfused livers of guinea pigs after acute experimental poisoning with As2O3. PHARMACOLOGY & TOXICOLOGY 1992; 70:352-6. [PMID: 1608923 DOI: 10.1111/j.1600-0773.1992.tb00486.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The effect of the dithiols British Anti-Kewisite (BAL), dimercaptopropanesulfonic acid (DMPS), dimercaptosuccinic acid (DMSA) and a new metal binding agent 2,3-bis-(acetylthio)- propanesulfonamide (BAPSA) on the biliary excretion of arsenic in perfused livers of guinea pigs after acute experimental poisoning with As2O3 was investigated. Guinea pigs received As2O3, 10.0 mg/kg subcutaneously at 9 a.m. as a single injection. One hour after the injection the livers were perfused (2.5 ml x min.-1 x g-1 liver) with Krebs-Henseleit buffer and glucose for 80 min. After 40 min. of saline perfusion (control) 0.1 or 0.7 mmol/l BAL, DMSA, DMPS, or BAPSA were added to the perfusate and arsenic elimination in the bile and effluent perfusate was measured. The biliary excretion of arsenic in control livers between 40 and 80 min. was 0.7% of the total arsenic liver content before perfusion (= arsenic liver content after perfusion + portion excreted in the bile+perfusate). After antidote addition (0.1 mmol/l) the excretion was 0.2% for livers perfused with BAL, 6.8% for DMSA, 10.6% for DMPS, and 11.1% for BAPSA, respectively. After 0.7 mmol/l antidote the excretion of arsenic was 0.1% in livers perfused with BAL, 9.6% for DMSA, 12.3% for DMPS, and 13.3% for BAPSA, respectively. Except BAL, all compounds and most effectively BAPSA increased biliary excretion of arsenic. This indicates that excretion of arsenic which normally is mainly renal is shifted towards faecal excretion by the dithiols.
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Affiliation(s)
- F X Reichl
- Walther Straub-Institut of Pharmacology and Toxicology, Ludwig-Maximilians-University of München, Germany
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Atawodi SE, Maduagwu EN. Pharmacokinetics of biliary excretion of N-nitrosodiphenylamine (NDPA) in animals of different species. Eur J Drug Metab Pharmacokinet 1990; 15:27-9. [PMID: 2384114 DOI: 10.1007/bf03190124] [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: 12/31/2022]
Abstract
Pharmacokinetic investigations into the biliary excretion of N-nitrosodiphenylamine given as an i.p. dose of 50 mg/kg were conducted and results compared in three animal species; rat, guinea pig and rabbit following bile duct cannulation and collection of bile in vitro. The guinea pig excreted NDPA into bile fastest while the rabbit, which excreted it slowest, eliminated it fastest. Both appearance and disappearance of the nitrosamine were comparatively slow in the rat. NDPA elimination half-life values in the animal species were 510, 240 and 95 min respectively, while cumulative excretions amounted to 12, 3 and 0.3 percent. The toxicological implications of these species differences are highlighted.
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Affiliation(s)
- S E Atawodi
- Department of Biochemistry, College of Medicine, University of Ibadan, Nigeria
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Siddik ZH, Newell DR, Boxall FE, Harrap KR. The comparative pharmacokinetics of carboplatin and cisplatin in mice and rats. Biochem Pharmacol 1987; 36:1925-32. [PMID: 3297068 DOI: 10.1016/0006-2952(87)90490-4] [Citation(s) in RCA: 99] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The plasma, urinary and biliary clearances of cisplatin and its non-nephrotoxic analogue, Carboplatin (cis-diammine-1,1-cyclobutane dicarboxylate platinum II, CBDCA, JM8) have been determined in mice and rats following intravenous administration of the compounds. The plasma concentration-time curves were biphasic during the time period studied (0-60 min), with t1/2 alpha of 2-3 min for both platinum complexes and t1/2 beta of 10-15 min for cisplatin and 25-26 min for Carboplatin. The kinetic rate constants, k12 and k21, were similar for both Carboplatin and cisplatin, indicating that there was no appreciable net accumulation of the compounds in the peripheral tissues. Immediately after administration, Carboplatin became reversibly bound to plasma proteins in vivo to the extent of about 20%. Appreciable irreversible binding appeared after the first 60 min and increased steadily, so that by 4 hr only 34% of the compound was present in the plasma as the free drug. In comparison, binding of cisplatin to plasma was exclusively irreversible and, after the first 10 min, free drug disappeared rapidly, such that by 60 min free platinum was not detectable. The plasma clearance of free cisplatin (26.1 ml/min/kg) was significantly greater than that of either Carboplatin (10.3 ml/min/kg) or insulin (10.1 ml/min/kg). The main route of excretion of the two platinum complexes was via the urine, with 80-90% of Carboplatin and 43-48% of cisplatin being excreted within 4 hr. In the rat, the Carboplatin excreted in the urine was predominantly as the unchanged compound. The renal clearance of cisplatin (12.3 ml/min/kg) was significantly greater than that of either Carboplatin (9.3 ml/min/kg) or insulin (9.6 ml/min/kg), suggesting that cisplatin was excreted by an active renal secretory mechanism whilst Carboplatin was eliminated by glomerular filtration alone. Biliary excretion of the two compounds was only 0.4-1.2% of the administered dose in 6 hr, with biliary clearance of cisplatin (0.27 ml/min/kg) being fivefold greater than that of Carboplatin (0.053 ml/min/kg). The results indicate that the major pharmacokinetic differences between Carboplatin and cisplatin relate to their renal handling and their reactivity with macromolecules. These differences may well underline the substantial lack of Carboplatin nephrotoxicity in comparison with cisplatin.
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Guarino AM. Aquatic versus mammalian toxicology: applications of the comparative approach. ENVIRONMENTAL HEALTH PERSPECTIVES 1987; 71:17-24. [PMID: 3297659 PMCID: PMC1474362 DOI: 10.1289/ehp.877117] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The large body of literature and techniques generated by mammalian toxicity studies provides a conceptual and technical framework within which the absorption, fate, and disposition of xenobiotics in aquatic organisms can be studied. This review emphasizes the similarities and differences between mammalian and aquatic systems, e.g., lung vs. gill as site of absorption and toxicity. These must be taken into consideration when designing aquatic toxicity studies. Studies of phenol red in dogfish shark as an example show physiologic-based pharmacokinetic modeling to be a useful tool for investigating and eventually predicting species differences in xenobiotic disposition and drug differences within the same species. This discussion demonstrates that both laboratory and modeling procedures are now available to carry out sophisticated studies of xenobiotic fate and disposition in fish. Such studies are needed to pinpoint sites and mechanisms of pollutant toxicity in aquatic organisms.
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Bowes SG, Renwick AG. The hepatic metabolism and biliary excretion of benzo[a]pyrene in guinea-pigs fed normal, high-fat or high-cholesterol diets. Xenobiotica 1986; 16:531-42. [PMID: 3751110 DOI: 10.3109/00498258609043542] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Approx. one-third of an i.v. dose of 14C-benzo[a]pyrene was excreted within four hours in the bile of guinea-pigs fed a normal diet. The extent of excretion was not altered by feeding high-fat or high-cholesterol diets. Hepatic cytochromes P-450 and b5, and benzo[a]pyrene hydroxylase activity were unaltered by the administration of high-fat and high-cholesterol diets. Pretreatment with low oral doses of benzo[a]pyrene (6 X 3 mg/kg) did not induce these parameters in animals given any of the diets. High-fat and high-cholesterol diets altered the pattern of benzo[a]pyrene metabolites in the bile, with significantly increased excretion of dihydrodiol glucuronides in both the high-fat and high-cholesterol groups. Hepatic epoxide hydrolase activity and glutathione content were unaltered by the high-fat or high-cholesterol diets, and therefore cannot explain the alteration in the profile of biliary metabolites of benzo[a]pyrene. The altered pattern of biliary excretion in animals fed high-fat or high-cholesterol diets would lead to an increase in the delivery to the colon of dihydrodiol metabolites of benzo[a]pyrene.
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Fleck C, Bräunlich H. Relation between renal and hepatic excretion of drugs: I. Phenol red in comparison with p-aminohippurate and indocyanine green. EXPERIMENTAL PATHOLOGY 1986; 29:179-92. [PMID: 3720909 DOI: 10.1016/s0232-1513(86)80019-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Phenol red is a suitable compound for the simultaneous assay of renal and hepatic excretion in the rat. Its elimination has been compared with those of p-aminohippurate (PAH) and indocyanine green (ICG) which are eliminated nearly exclusively via kidneys or liver, respectively. The interruption of one elimination route one day before the experiment, that means bile duct ligation (DL) in the case of ICG or bilateral nephrectomy (NX) in the case of PAH are followed by a slight increase in the elimination via the alternative pathway, but no effective compensation occurs. On the other hand, the renal excretion of phenol red is significantly increased after DL only following administration of high doses. This intensification is caused by an increase in the unbound amount of phenol red depending on the plasma concentration and reflects an enhanced glomerular filtration fraction. The biliary excretion increases significantly after NX, but only after infusion of low doses. The maximal biliary secretion capacity cannot be exceeded following NX, either. The competitive inhibition of phenol red excretion by probenecid supports the findings of NX or DL experiments. An influence of the three test substances on arterial blood pressure has been excluded. The most important factors influencing the switch over from one to the other elimination route seem to be at least in the case of phenol red the amount of unbound substance, the influence of the administered dose on the glomerular filtration, and disturbances in the volume of distribution, e.g. the possible reduction of hepatic uptake after DL.
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Abstract
Species difference in the biliary excretion of methylmercury was studied in male rats, mice, rabbits and guinea pigs. The rates of mercury excretion (% dose/2 hr) into the bile of the rats, mice, rabbits and guinea pigs during the 2 hr from 2 to 4 hr after the administration of methylmercury were 0.61, 0.091, 0.036 and 0.019, respectively. These results suggest that biliary excretion and enterohepatic circulation of methylmercury in the latter three species may not influence the fate of this compound as significantly as in rats. Most of the methylmercury excreted into the bile of rats was bound to glutathione (GSH). In the mouse bile, 40% of the methylmercury was bound to GSH and the rest was found in a fraction eluted at the void volume of the Sephadex G-15 column. However, in the case of the rabbits and guinea pigs, methylmercury-GSH was scarcely detectable in the bile and almost all of the methylmercury was eluted at the void volume of the column.
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24
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Galtier P, Coche Y, Alvinerie M. Tissue distribution and elimination of [3H]levamisole in the rat after oral and intramuscular administration. Xenobiotica 1983; 13:407-13. [PMID: 6659543 DOI: 10.3109/00498258309052278] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Total radioactivity and drug concentrations were determined in plasma, organs and excreta of male rats given a single oral or intramuscular dose (7.5 mg/kg) of [3H]levamisole. The anthelmintic drug was distributed mostly within the digestive contents after oral administration and in kidneys and liver after intramuscular injection. The parent drug accounted only for 32 to 45% of total radioactivity in plasma and it appeared metabolized in both urine and bile. The urine (0-72 h) contained 68-78% of the radioactive dose, as parent drug and other tritiated materials. The 4-hydroxylation of levamisole did not represent a major metabolic pathway of the drug in the rat.
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Cocchetto DM, Bjornsson TD. Methods for vascular access and collection of body fluids from the laboratory rat. J Pharm Sci 1983; 72:465-92. [PMID: 6345750 DOI: 10.1002/jps.2600720503] [Citation(s) in RCA: 72] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Layiwola PJ, Linnecar DF, Knights B. The biotransformation of three 14C-labelled phenolic compounds in twelve species of freshwater fish. Xenobiotica 1983; 13:107-13. [PMID: 6880238 DOI: 10.3109/00498258309052244] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
1. The urinary and biliary excretion of 14C-labelled m-cresol, 1-naphthol and o-chlorophenol were investigated in 12 species of freshwater fish (bitterling, Rhodeus sericeus amarus; bream, Abramis brama; crucian carp, Carassius carassius; goldfish, Carassius auratus; gudgeon, Gobio gobio; guppy, Poecilia reticulata; minnow, Phoximus phoximus; perch, Perca fluviatilis; roach, Rutilus rutilus; rudd, Scardinius erythropthalmus; three-spined stickleback, Gasterosteus aculeatus; tench, Tinca tinca) when immersed in sub-lethal concentrations of the compounds in the aquarium water for 48 h. 2. The sulphate and glucuronic acid conjugates of 1-naphthol and o-chlorophenol were detected in both the aquarium water and the bile of all the fish species. 3. The oxidation product of m-cresol, m-hydroxybenzoic acid, and the sulphate conjugate of the phenol, were excreted into the aquarium water of all species except the guppy, which did not excrete m-hydroxybenzoic acid. In addition to these two metabolites, the glucuronic acid conjugate of m-cresol was found in the bile of all species, except for guppies whose small size precluded study of biliary excretion.
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27
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Dixon PA. Sulphation and diglucuronidation as constraints to enterohepatic circulation of dichlorophen in rats. J Pharm Pharmacol 1982; 34:596-7. [PMID: 6127389 DOI: 10.1111/j.2042-7158.1982.tb04803.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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28
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Gregus Z, Klaassen CD. Comparison of Biliary excretion of organic anions in mice and rats. Toxicol Appl Pharmacol 1982; 63:13-20. [PMID: 6176049 DOI: 10.1016/0041-008x(82)90021-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Lener J, Bíbr B. Biliary excretion and tissue distribution of penta- and hexavalent molybdenum in rats. Toxicol Appl Pharmacol 1979; 51:259-63. [PMID: 531891 DOI: 10.1016/0041-008x(79)90468-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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31
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Siddik ZH, Barnes RD, Dring LG, Smith RL, Williams RT. The fate of lysergic acid DI[14C]ethylamide ([14C]LSD) in the rat, guinea pig and rhesus monkey and of [14C]iso-LSD in rat. Biochem Pharmacol 1979; 28:3093-101. [PMID: 117811 DOI: 10.1016/0006-2952(79)90618-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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32
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James GW, Kennewell PD, Taylor JB, Luscombe DK, Nicholls PJ. Studies on the absorption, distribution and elimination of 6-o-chlorophenyl-2,4-dihydro-2(N-methyl-piperazin-1-yl)-methylene-8-nitro-1H-imidazo[1,2-a] [1,4]benzodiazepin-1-one methanesulphonate in the male rat and rabbit. Eur J Drug Metab Pharmacokinet 1979; 4:15-21. [PMID: 38121 DOI: 10.1007/bf03189394] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The fate of a novel imidazo-benzodiazepine (I) was studied in male rats and rabbits using 14C and 3H-labelled I. In both species the compound was rapidly and widely absorbed after an oral dose of 5 mg/kg to give peak tissue and plasma levels after 1 hour in the rat and 4 hours in the rabbit. The highest concentrations of radioactivity were present in the liver (rat) and liver, kidney and subcutaneous fat (rabbit). Plasma levels of radioactivity fell to 3% of the maximum value in 24 hours in the rat but 48 hours were required for a similar fall in the rabbit. The main route of elimination of radioactivity was via the bile followed by excretion in the faeces. For the rat the rate of biliary elimination was 16.6% of the administered dose/hour; for the rabbit this rate was 5.6%/hour. Recovery of administered radioactivity during 0-24 hours for urine and faeces respectively was 4.8% and 69% for the rat and 23.2% and 10.9% for the rabbit. Up to 97% of the radioactivity administered to rats could be recovered in the excreta in the 7 days following dosing. Up to 90% of the dose administered to rabbits appeared in the excreta during 10 days. No unchanged (I) could be detected in the urine or bile. The radioactive metabolites were polar products, some of which were in the form of glucuronide conjugates.
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Emudianughe TS, Caldwell J, Dixon PA, Smith RL. Studies on the metabolism of arylacetic acids. 5. The metabolic fate of 2-naphthylacetic acid in the rat, rabbit and ferret. Xenobiotica 1978; 8:525-34. [PMID: 695696 DOI: 10.3109/00498257809061252] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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35
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Barford PA, Olavesen AH, Curtis CG, Powell GM. Biliary excretion of some anionic derivatives of diethylstilboestrol and phenolphthalein in the guinea pig. Biochem J 1977; 168:373-7. [PMID: 606240 PMCID: PMC1183782 DOI: 10.1042/bj1680373] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The metabolic fates and modes of excretion of diethylstilboestrol mono[35S]sulphate and diethylstilboestrol di[35S]sulphate were studied in the guinea pig. Comparative studies were also made with [G-3H]diethylstilboestrol and phenolphthalein di[35S]sulphate. Diethylstiboesterol di[35S]sulphate was extensively eliminated in the bile unchanged. After administration of diethylstilboestrol mono[35S]sulphate, extensive biliary elimination of radioactivity was also recorded. Radioactive components were identified as diethylstilboestrol disulphate, diethylstilboestrol monosulphate monoglucuronide and unchanged diethylstilboestrol monosulphate. When [G-3H]diethylstilboestrol was administered, 3H-labelled diethylstilboestrol monoglucuronide, diethylstilboestrol monosulphate monoglucuronide and diethylstilboestrol disulphate appeared in the bile. Phenolphthalein di[35S]sulphate was excreted unchanged in bile. These findings are discussed in relation to studies carried out in the rat [Barford, Olavesen, Curtis & Powell (1977) Biochem. J. 164, 423--430] and species differences are related to differences in enzyme activities in rat and guinea-pig liver.
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Barford PA, Olavesen AH, Curtis CG, Powell GM. Metabolic fates of diethylstilboestrol sulphates in the rat. Biochem J 1977; 164:423-30. [PMID: 880247 PMCID: PMC1164808 DOI: 10.1042/bj1640423] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The metabolic fates and modes of excretion of diethylstilboestrol mono[35S]sulphate and diethylstilboestrol di[35S]sulphate were studied in the rat. Both of the esters were desulphated to some extent in vivo. In addition, significant amounts of radioactivity appeared in the bile as diethylstilboestrol mono[35S]sulphate monoglucuronide. The percentage of the dose appearing in bile as the diconjugate was substantially greater in experiments with diethylstilboestrol mono[35S]sulphate than with diethylstilboestrol di[35S]sulphate. Whole-body radioautography and studies with isolated perfused liver confirmed the liver as the major metabolic organ for both esters. When the metabolite diethylstilboestrol mono[35S]sulphate monoglucuronide isolated from the bile was reinjected, it was excreted in the bile unchanged. Studies in vitro demonstrated that both esters were substrates for arylsulphatase C with Km values in the range 52-76 micrometer. The metabolic fates and modes of excretion of the esters are discussed in relation to the enzyme complement of rat liver.
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Meyer T. The metabolism of biphenyl. IV. Phenolic metabolites in the guinea pig and the rabbit. ACTA PHARMACOLOGICA ET TOXICOLOGICA 1977; 40:193-200. [PMID: 576550 DOI: 10.1111/j.1600-0773.1977.tb02068.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The phenolic metabolites of biphenyl in guinea pigs and rabbits were qualitatively and quantitatively analysed as trimethylsilyl (TMS) ethers by combined gas chromatography/mass spectrometry and gas chromatography, respectively. The parent compound was hydroxylated to monohydroxylated biphenyls and minor amounts of dihydroxylated derivatives, and the main route of body clearance appeared to be by the urine in both species. Thus, in the urine of guinea pigs 32.9% of the dose was detected 96 hrs after dosing, while the major part (29.5%) was eliminated during the first day as conjugates. The main metabolite was 4-hydroxybiphenyl (25.5%). During the first 24 hrs faecal recovery was 20.3% of the dose, and most of this (14.3%) consisted of biphenyl itself. Biliary excretion of the metabolites of biphenyl origin amounted to 3.3% of the dose during the first day, and 4-hydroxybiphenyl was the major metabolite. In the urine of rabbits 49.1% of the dose was recovered 96 hrs after dosing, and most of this (25.4 and 15.9%, respectively) was eliminated during the first two days as conjugates. The major metabolite was 4-hydroxybiphenyl (35.3%). On the first day faecal recovery was 1.6%, of which 1.4% was detected as biphenyl itself. Less than 1% of the dose was found in the 7 hrs rabbit bile, and exclusively as 4-hydroxybiphenyl. The experiments thus show that both qualitative and quantitative differences in the metabolism of biphenyl exist between the guinea pig and the rabbit even though 4-hydroxybiphenyl was the most prominent metabolite of biphenyl in both species.
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Tse JW, Wiebe LI, Ediss C, Shysh A. Clearance and elimination of 125I-Rose Bengal in the sub-totally nephrectomized chronically uremic rat. INTERNATIONAL JOURNAL OF NUCLEAR MEDICINE AND BIOLOGY 1976; 3:134-7. [PMID: 1002387 DOI: 10.1016/0047-0740(76)90082-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Abstract
1. After oral administration of (14C) trazodone HCl (4 mg/kg) to rabbits, the blood level of radioactivity shows a peak at 3 h; unchanged trazodone concentration in brain is higher than that in plasma at 3 h after dosage. 29 The metabolic fate of trazodone in rabbits is different from that in rats and a new, basic metabolite is present in rabbit liver, brain, plasma and urine. 3. The concentration pattern in blood of humans given a single dosage (50 mg) of trazodone HCl is similar to that in rabbits rather than that in rats. 4. The rate of metabolism of trazodone by liver microsomes from mice is approximately 1-5 times higher than that with rat or rabbit liver microsomes.
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Abou-El-Makarem MM, Bock KW. UDP-glucuronyltransferase in perfused rat liver and in microsomes. Glucuronidation of bilirubin. EUROPEAN JOURNAL OF BIOCHEMISTRY 1976; 62:411-6. [PMID: 815089 DOI: 10.1111/j.1432-1033.1976.tb10173.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In perfused rat liver and in fistula rats the formation of bilirubin conjugates was studied after labeling with [14C]bilirubin,5-amino [14C]levulinic acid and [14C]hemin. The latter two compounds were used to study heme degradation to bilirubin from intrahepatic and extrahepatic sources, respectively. Bilirubin glucuronides were the major conjugates in fistula bile. In liver perfusion bile the proportion of non-glucuronide conjugates was increased. After a high dose of hemin (2.5 mumol) bilirubin glucuronides were decreased compared with other bilirubin conjugates both in fistula bile and in liver perfusion bile. In addition green pigments were formed. These alterations were reversed in chronically hemin-treated rats in which heme oxygenase had been induced. The interference of UDP-glucose and UDP-glucuronic acid with bilirubin glucuronidation and glucosidation was studied in liver microsomes. UDP-glucose did not affect bilirubin glucuronidation in native microsomes in which UDP-glucuronyltransferase activity is constrained. When this constraint was released by various treatments altering membrane structure UDP-glucose markedly inhibited bilirubin glucuronidation. However, under these conditions bilirubin glucosidation was unaffected by UDP-glucuronic acid. The results suggest that the release of the constraint of UDP-glucuronyltransferase in vivo may lead to a decrease of the proportion of bilirubin glucuronides to other bilirubin conjugates in bile.
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Caldwell J, Köster U, Smith RL, Williams RT. Species variations in the N-oxidation of chlorphentermine. Biochem Pharmacol 1975; 24:2225-32. [PMID: 814901 DOI: 10.1016/0006-2952(75)90259-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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45
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Abstract
The biliary route is very important for the elimination of some foreign compounds from the body. For many of these compounds, an increase in the rate at which they are excreted into the bile will decrease their toxicity and vice versa. A number of factors which are known to alter the biliary excretion of xenobiotics, as well as the current concepts of the physiological mechanisms responsible for the excretion of foreign compounds, have been enumerated. However, much remains still to be understood; essentially nothing is known at the subcellular level about the biliary excretion of foreign compounds. It has recently been concluded that our knowledge of the biliary excretion of compounds is about 40 years behind that of the renal excretion mechanism.
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Abstract
1. [14C]Metronidazole was rapidly absorbed from the gastro-intestinal tract of rats giving maximum blood levels of radioactivity, equivalent to 6-4 and 6-7 mug metronidazole per ml blood, 1 h after oral dosing. 2. There was rapid equilibration between blood and most tissues, although radioactivity was concentrated in the liver, kidney, gastro-intestinal tract and vaginal secretions. 3. The half-life of clearance of radioactivity from the majority of tissues was between 3 and 4 h, although it was longer in the skin (8 h) and gastro-intestinal tract (14 h). 4. Fourteen radioactive excretion products were detected in rat urine and all the major products were identified. These all contained a nitro group and represented 97 degrees of the total radioactivity excreted in urine. 5. Unchanged metronidazole was secreted throughout the entire length of the gastro-intestinal tract and into the vagina of rats. 6. A hypothesis has been proposed to explain the high clinical efficacy of metronidazole in treating trichomonal and amoebic infections.
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48
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Wood BA, Stopher DA, Monro AM. The metabolism of tolamolol in the mouse, rat, guinea-pig, rabbit and dog. Xenobiotica 1975; 5:183-95. [PMID: 1174392 DOI: 10.3109/00498257509056104] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
1. [3H, 14C]Tolamolol was well absorbed after oral administration to mice, rats, guinea-pigs, rabbits and dogs. 2. The major route for excretion of radioactivity by mice, rats and guinea-pigs was the faeces; in rabbits the major route was the urine. Dogs excreted similar amounts of radioactivity by both routes. Biliary excretion of radioactivity by the rat and guinea-pig was demonstrated. 3. Tolamolol was extensively metabolized by all five species. The major metabolite in mice, rats, guinea-pigs and rabbits was the product of hydroxylation of the tolyl ring, which was excreted as such as the glucuronide and sulphate conjugates. 4. In the dog the major metabolite was the acid resulting from hydrolysis of the carbamoyl group. This acid was also excreted by the rabbit, but was only a minor metabolite in the other species studied.
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49
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Andoh BY, Renwick AG, Williams RT. The excretion of (35S)dapsone and its metabolites in the urine, faeces and bile of the rat. Xenobiotica 1974; 4:571-83. [PMID: 4432536 DOI: 10.3109/00498257409052098] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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50
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Hughes RD, Millburn P, Williams RT. Molecular weight as a factor in the excretion of monoquaternary ammonium cations in the bile of the rat, rabbit and guinea pig. Biochem J 1973; 136:967-78. [PMID: 4786541 PMCID: PMC1166046 DOI: 10.1042/bj1360967] [Citation(s) in RCA: 41] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
1. The excretion in the bile and urine of intraperitoneally injected (14)C-labelled monoquaternary ammonium or pyridinium cations was measured in bile-duct-cannulated rats (ten compounds) and in guinea pigs and rabbits (six compounds). 2. Seven of these, namely N-methylpyridinium, tetraethylammonium, trimethylphenylammonium, diethylmethylphenylammonium, methylphenyldipropylammonium, dibenzyldimethylammonium and tribenzylmethylammonium, were excreted largely unchanged in the bile and urine. 3. 3-Hydroxyphenyltrimethylammonium, 3-bromo-N-methylpyridinium and cetyltrimethylammonium were metabolized to an appreciable extent in the rat. 4. In intact rats intraperitoneally injected trimethylphenylammonium (mol.wt. 136) was excreted mainly in the urine, dibenzyldimethylammonium (mol.wt. 226) was excreted in roughly equal amounts in the urine and faeces, and tribenzylmethylammonium (mol.wt. 302) was excreted mainly in the faeces. The faecal excretion of these compounds corresponded to their biliary excretion in bile-duct-cannulated rats. About 3-4% of tribenzyl[(14)C]methylammonium was eliminated as (14)CO(2). 5. In rats the extent of biliary excretion of four cations with molecular weights in the range 94-164 was less than 10% of the dose, whereas that of five cations with molecular weights 173-302 was greater than 10%. These results and other data from the literature suggested that the molecular weight needed for the biliary excretion of such cations to an extent of 10% or more of the dose was about 200+/-50. Studies with six cations in guinea pigs and rabbits suggest that this value applies also to these species. 6. The results suggest that the threshold molecular weight for the appreciable (>10%) biliary excretion of monoquaternary cations is different from that for anions (Millburn et al., 1967a; Hirom et al., 1972b). With rats, guinea pigs and rabbits, no significant species difference was noted, whereas with anions there is a marked species difference.
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