1
|
Frąckowiak-Wojtasek B, Gąsowska-Bajger B, Tarasek D, Mytnik M, Wojtasek H. Oxidation of anti-thyroid drugs and their selenium analogs by ABTS radical cation. Bioorg Chem 2023; 141:106891. [PMID: 37788560 DOI: 10.1016/j.bioorg.2023.106891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 09/22/2023] [Accepted: 09/25/2023] [Indexed: 10/05/2023]
Abstract
Lactoperoxidase was previously used as a model enzyme to test the inhibitory activity of selenium analogs of anti-thyroid drugs with 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) as a substrate. Peroxidases oxidize ABTS to a metastable radical ABTS•+, which is readily reduced by many antioxidants, including thiol-containing compounds, and it has been used for decades to measure antioxidant activity in biological samples. We showed that anti-thyroid drugs 6-n-propyl-2-thiouracil, methimazole, and selenium analogs of methimazole also reduced it rapidly. This reaction may explain the anti-thyroid action of many other compounds, particularly natural antioxidants, which may reduce the oxidized form of iodine and/or tyrosyl radicals generated by thyroid peroxidase thus decreasing the production of thyroid hormones. However, influence of selenium analogs of methimazole on the rate of hydrogen peroxide consumption during oxidation of ABTS by lactoperoxidase was moderate. Direct hydrogen peroxide reduction, proposed before as their mechanism of action, cannot therefore account for the observed inhibitory effects. 1-Methylimidazole-2-selone and its diselenide were oxidized by ABTS•+ to relatively stable seleninic acid, which decomposed slowly to selenite and 1-methylimidazole. In contrast, oxidation of 1,3-dimethylimidazole-2-selone gave selenite and 1,3-dimethylimidazolium cation. Accumulation of the corresponding seleninic acid was not observed.
Collapse
Affiliation(s)
| | | | - Damian Tarasek
- Institute of Chemistry, Opole University, Ul. Oleska 48, 45-052 Opole, Poland
| | - Martyna Mytnik
- Institute of Chemistry, Opole University, Ul. Oleska 48, 45-052 Opole, Poland
| | - Hubert Wojtasek
- Institute of Chemistry, Opole University, Ul. Oleska 48, 45-052 Opole, Poland.
| |
Collapse
|
2
|
Ferreira ADO, Polonini H, da Silva SL, Aglio NCB, Abreu J, Fernandes BMA. Stability of Acetazolamide, Baclofen, Dipyridamole, Mebeverine Hydrochloride, Propylthiouracil, Quinidine Sulfate, and Topiramate Oral Suspensions in SyrSpend SF PH4. Int J Pharm Compd 2017; 21:339-346. [PMID: 28719377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The objective of this study was to evaluate the stability of 7 commonly used active pharmaceutical ingredients compounded in oral suspensions using an internationally used suspending vehicle (SyrSpend SF PH4): acetazolamide 25.0 mg/mL, baclofen 10.0 mg/mL, dipyridamole 10.0 mg/mL, mebeverine hydrochloride 10.0 mg/mL, propylthiouracil 5.0 mg/mL, quinidine sulfate 10.0 mg/mL, and topiramate 5.0 mg/mL. All suspensions were stored both at controlled refrigerated (2°C to 8°C) and room temperature (20°C to 25°C). Stability was assessed by measuring the percentage recovery at varying time points throughout a 90-day period. Active pharmaceutical ingredient quantification was performed by ultraviolet (UV) high-performance liquid chromatography, via a stability-indicating method. Given the percentage of recovery of the active pharmaceutical ingredients within the suspensions, the beyond-use date of the final products (active pharmaceutical ingredient + vehicle) was at least 90 days for all suspensions with regards to both temperatures. This suggests that SyrSpend SF PH4 is suitable for compounding active pharmaceutical ingredients from different pharmacological classes.
Collapse
Affiliation(s)
| | - Hudson Polonini
- Ortofarma - Quality Control Laboratories, Matias Barbosa, MG, Brazil
| | | | | | - Jordana Abreu
- Federal University of Juiz de Fora, Juiz de Fora, MG, Brazil
| | - Brandão Marcos Antônio Fernandes
- Ortofarma - Quality Control Laboratories, Matias Barbosa, MG, Brazil
- Federal University of Juiz de Fora, Juiz de Fora, MG, Brazil
| |
Collapse
|
3
|
Melis M, Arca M, Aragoni MC, Cabras T, Caltagirone C, Castagnola M, Crnjar R, Messana I, Tepper BJ, Tomassini Barbarossa I. Dose-Dependent Effects of L-Arginine on PROP Bitterness Intensity and Latency and Characteristics of the Chemical Interaction between PROP and L-Arginine. PLoS One 2015; 10:e0131104. [PMID: 26103639 PMCID: PMC4477953 DOI: 10.1371/journal.pone.0131104] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 05/28/2015] [Indexed: 11/19/2022] Open
Abstract
Genetic variation in the ability to taste the bitterness of 6-n-propylthiouracil (PROP) is a complex trait that has been used to predict food preferences and eating habits. PROP tasting is primarily controlled by polymorphisms in the TAS2R38 gene. However, a variety of factors are known to modify the phenotype. Principle among them is the salivary protein Ps-1 belonging to the basic proline-rich protein family (bPRP). Recently, we showed that oral supplementation with Ps-1 as well as its related free amino acids (L-Arg and L-Lys) enhances PROP bitterness perception, especially for PROP non-tasters who have low salivary levels of Ps-1. Here, we show that salivary L-Arg levels are higher in PROP super-tasters compared to medium tasters and non-tasters, and that oral supplementation with free L-Arg enhances PROP bitterness intensity as well as reduces bitterness latency in a dose-dependent manner, particularly in individuals with low salivary levels of both free L-Arg and Ps-1 protein. Supplementation with L-Arg also enhanced the bitterness of caffeine. We also used 1H-NMR spectroscopy and quantum-mechanical calculations carried out by Density Functional Theory (DFT) to characterize the chemical interaction between free L-Arg and the PROP molecule. Results showed that the -NH2 terminal group of the L-ArgH+ side chain interacts with the carbonyl or thiocarbonyl groups of PROP by forming two hydrogen bonds with the resulting charged adduct. The formation of this PROP•ArgH+ hydrogen-bonded adduct could enhance bitterness intensity by increasing the solubility of PROP in saliva and its availability to receptor sites. Our data suggest that L-Arg could act as a 'carrier' of various bitter molecules in saliva.
Collapse
Affiliation(s)
- Melania Melis
- Department of Biomedical Sciences, Section of Physiology, University of Cagliari, Monserrato, CA, Italy
| | - Massimiliano Arca
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, Monserrato, CA, Italy
| | - Maria Carla Aragoni
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, Monserrato, CA, Italy
| | - Tiziana Cabras
- Department of Life and Environment Sciences, Macrosection of Biomedicine, University of Cagliari, Monserrato, CA, Italy
| | - Claudia Caltagirone
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, Monserrato, CA, Italy
| | - Massimo Castagnola
- Institute of Biochemistry and Clinical Biochemistry, Catholic University, Rome, Italy
| | - Roberto Crnjar
- Department of Biomedical Sciences, Section of Physiology, University of Cagliari, Monserrato, CA, Italy
| | - Irene Messana
- Department of Life and Environment Sciences, Macrosection of Biomedicine, University of Cagliari, Monserrato, CA, Italy
| | - Beverly J. Tepper
- Department of Food Science, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, New Jersey, United States of America
| | - Iole Tomassini Barbarossa
- Department of Biomedical Sciences, Section of Physiology, University of Cagliari, Monserrato, CA, Italy
| |
Collapse
|
4
|
Bastian TW, Prohaska JR, Georgieff MK, Anderson GW. Fetal and neonatal iron deficiency exacerbates mild thyroid hormone insufficiency effects on male thyroid hormone levels and brain thyroid hormone-responsive gene expression. Endocrinology 2014; 155:1157-67. [PMID: 24424046 PMCID: PMC3929725 DOI: 10.1210/en.2013-1571] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Fetal/neonatal iron (Fe) and iodine/TH deficiencies lead to similar brain developmental abnormalities and often coexist in developing countries. We recently demonstrated that fetal/neonatal Fe deficiency results in a mild neonatal thyroidal impairment, suggesting that TH insufficiency contributes to the neurodevelopmental abnormalities associated with Fe deficiency. We hypothesized that combining Fe deficiency with an additional mild thyroidal perturbation (6-propyl-2-thiouracil [PTU]) during development would more severely impair neonatal thyroidal status and brain TH-responsive gene expression than either deficiency alone. Early gestation pregnant rats were assigned to 7 different treatment groups: control, Fe deficient (FeD), mild TH deficient (1 ppm PTU), moderate TH deficient (3 ppm PTU), severe TH deficient (10 ppm PTU), FeD/1 ppm PTU, or FeD/3 ppm PTU. FeD or 1 ppm PTU treatment alone reduced postnatal day 15 serum total T4 concentrations by 64% and 74%, respectively, without significantly altering serum total T3 concentrations. Neither treatment alone significantly altered postnatal day 16 cortical or hippocampal T3 concentrations. FeD combined with 1 ppm PTU treatment produced a more severe effect, reducing serum total T4 by 95%, and lowering hippocampal and cortical T3 concentrations by 24% and 31%, respectively. Combined FeD/PTU had a more severe effect on brain TH-responsive gene expression than either treatment alone, significantly altering Pvalb, Dio2, Mbp, and Hairless hippocampal and/or cortical mRNA levels. FeD/PTU treatment more severely impacted cortical and hippocampal parvalbumin protein expression compared with either individual treatment. These data suggest that combining 2 mild thyroidal insults during development significantly disrupts thyroid function and impairs TH-regulated brain gene expression.
Collapse
Affiliation(s)
- Thomas W Bastian
- Department of Pharmacy Practice and Pharmaceutical Sciences (T.W.B., G.W.A.), College of Pharmacy, University of Minnesota Duluth, Duluth, Minnesota 55812; Department of Biomedical Sciences (J.R.P.), University of Minnesota Medical School Duluth, Duluth, Minnesota 55812; Department of Pediatrics and Center for Neurobehavioral Development (M.K.G.), School of Medicine, University of Minnesota, Minneapolis, Minnesota 55454
| | | | | | | |
Collapse
|
5
|
Marchiori A, Capece L, Giorgetti A, Gasparini P, Behrens M, Carloni P, Meyerhof W. Coarse-grained/molecular mechanics of the TAS2R38 bitter taste receptor: experimentally-validated detailed structural prediction of agonist binding. PLoS One 2013; 8:e64675. [PMID: 23741366 PMCID: PMC3669430 DOI: 10.1371/journal.pone.0064675] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 04/16/2013] [Indexed: 11/19/2022] Open
Abstract
Bitter molecules in humans are detected by ∼25 G protein-coupled receptors (GPCRs). The lack of atomic resolution structure for any of them is complicating an in depth understanding of the molecular mechanisms underlying bitter taste perception. Here, we investigate the molecular determinants of the interaction of the TAS2R38 bitter taste receptor with its agonists phenylthiocarbamide (PTC) and propylthiouracil (PROP). We use the recently developed hybrid Molecular Mechanics/Coarse Grained (MM/CG) method tailored specifically for GPCRs. The method, through an extensive exploration of the conformational space in the binding pocket, allows the identification of several residues important for agonist binding that would have been very difficult to capture from the standard bioinformatics/docking approach. Our calculations suggest that both agonists bind to Asn103, Phe197, Phe264 and Trp201, whilst they do not interact with the so-called extra cellular loop 2, involved in cis-retinal binding in the GPCR rhodopsin. These predictions are consistent with data sets based on more than 20 site-directed mutagenesis and functional calcium imaging experiments of TAS2R38. The method could be readily used for other GPCRs for which experimental information is currently lacking.
Collapse
Affiliation(s)
- Alessandro Marchiori
- International School for Advanced Studies (SISSA-ISAS), Neuroscience Sector, Trieste, Italy
- Computational Biophysics, German Research School for Simulation Sciences, Juelich, Germany
- Department of Molecular Genetics, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), Nuthetal, Germany
| | - Luciana Capece
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
- Computational Biophysics, German Research School for Simulation Sciences, Juelich, Germany
- Institute for Advanced Simulation IAS-5, Computational Biomedicine, Forschungszentrum Juelich, Juelich, Germany
| | - Alejandro Giorgetti
- Computational Biophysics, German Research School for Simulation Sciences, Juelich, Germany
- Department of Biotechnology, University of Verona, Verona, Italy
| | - Paolo Gasparini
- Institute for Maternal and Child Health - IRCCS “Burlo Garofolo”, Trieste, Italy
| | - Maik Behrens
- Department of Molecular Genetics, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), Nuthetal, Germany
| | - Paolo Carloni
- Computational Biophysics, German Research School for Simulation Sciences, Juelich, Germany
- Institute for Advanced Simulation IAS-5, Computational Biomedicine, Forschungszentrum Juelich, Juelich, Germany
| | - Wolfgang Meyerhof
- Department of Molecular Genetics, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), Nuthetal, Germany
| |
Collapse
|
6
|
Melis M, Aragoni MC, Arca M, Cabras T, Caltagirone C, Castagnola M, Crnjar R, Messana I, Tepper BJ, Barbarossa IT. Marked increase in PROP taste responsiveness following oral supplementation with selected salivary proteins or their related free amino acids. PLoS One 2013; 8:e59810. [PMID: 23555788 PMCID: PMC3610910 DOI: 10.1371/journal.pone.0059810] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 02/18/2013] [Indexed: 11/17/2022] Open
Abstract
The genetic predisposition to taste 6-n-propylthiouracil (PROP) varies among individuals and is associated with salivary levels of Ps-1 and II-2 peptides, belonging to the basic proline-rich protein family (bPRP). We evaluated the role of these proteins and free amino acids that selectively interact with the PROP molecule, in modulating bitter taste responsiveness. Subjects were classified by their PROP taster status based on ratings of perceived taste intensity for PROP and NaCl solutions. Quantitative and qualitative determinations of Ps-1 and II-2 proteins in unstimulated saliva were performed by HPLC-ESI-MS analysis. Subjects rated PROP bitterness after supplementation with Ps-1 and II-2, and two amino acids (L-Arg and L-Lys) whose interaction with PROP was demonstrated by (1)H-NMR spectroscopy. ANOVA showed that salivary levels of II-2 and Ps-1 proteins were higher in unstimulated saliva of PROP super-tasters and medium tasters than in non-tasters. Supplementation of Ps-1 protein in individuals lacking it in saliva enhanced their PROP bitter taste responsiveness, and this effect was specific to the non-taster group.(1)H-NMR results showed that the interaction between PROP and L-Arg is stronger than that involving L-Lys, and taste experiments confirmed that oral supplementation with these two amino acids increased PROP bitterness intensity, more for L-Arg than for L-Lys. These data suggest that Ps-1 protein facilitates PROP bitter taste perception and identifies a role for free L-Arg and L-Lys in PROP tasting.
Collapse
Affiliation(s)
- Melania Melis
- Department of Biomedical Sciences, Section of Physiology, University of Cagliari, Monserrato, Italy
| | - Maria Carla Aragoni
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, Monserrato, Italy
| | - Massimiliano Arca
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, Monserrato, Italy
| | - Tiziana Cabras
- Department of Life and Environment Sciences, Macrosection of Biomedicine, University of Cagliari, Monserrato, Italy
| | - Claudia Caltagirone
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, Monserrato, Italy
| | - Massimo Castagnola
- Institute of Biochemistry and Clinical Biochemistry, Catholic University, Rome, Italy
| | - Roberto Crnjar
- Department of Biomedical Sciences, Section of Physiology, University of Cagliari, Monserrato, Italy
| | - Irene Messana
- Department of Life and Environment Sciences, Macrosection of Biomedicine, University of Cagliari, Monserrato, Italy
| | - Beverly J. Tepper
- Department of Food Science, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, New Jersey, United States of America
| | | |
Collapse
|
7
|
National Toxicology Program. Propylthiouracil. Rep Carcinog 2011; 12:369-70. [PMID: 21863091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
|
8
|
Abstract
Scientific evidence indicates that exogenous phospholipids in the form of liposomes can affect cell growth. Effects of liposomes on cell growth depend on several factors including composition of liposomes, lipid concentration, and type of cells studied. Because phagocytic cells such as monocytes and macrophages are natural targets of liposomes, intracellular delivery of drugs to modulate cellular activity of these cells is of interest. We explored the effects of phospholipid-based liposomes composed of soy bean phosphatidylcholine (PC) as the main lipid component on U-937 cell growth. Effects of charge-imposing lipids and cholesterol were also studied. In addition, we investigated whether phospholipid-based liposomes would exert any interaction on cell growth with propylthiouracil, a drug with known antiproliferative activity. We found that PC in the form of extruded liposomes had intrinsic antiproliferative activity on U-937 cells at concentrations of 200 microM and up without any appreciable cytotoxicity. Phosphatidylserine and phosphatidylglycerol, but not dicetlylphosphate, at 10 mol% increased growth retardation activity of PC liposomes. Cholesterol at 30 mol% did not have any effect on cell growth, except for liposomes composed of PC and phosphatidylserine, where growth retardation was negated in the presence of cholesterol. Synergistic effect on cell growth was seen with certain liposome compositions when 5.5 microg/mL of propylthiouracil was coincubated. The results of this study suggest that the effects of exogenous lipids on cell growth should be taken into consideration when PC-based liposomes are to be used as drug delivery systems, especially when the targets are cells with phagocytic activity.
Collapse
Affiliation(s)
- Utsana Puapermpoonsiri
- Department of Pharmacy, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand
| | | | | |
Collapse
|
9
|
Abstract
Propylthiouracil, a lyophobic drug with an antiproliferative activity, was formulated into niosomes using various classes of nonionic surfactants. Feasibility of vesicle formation by the sonication method was evaluated. Size and size distribution was measured by laser diffraction. Entrapment and drug release over 24 h were monitored by UV spectrophotometric method at 275 nm. The results revealed that niosomes readily formed from various compositions of nonionic surfactant and cholesterol, with or without a stabilizer. Entrapment of PTU in niosomes depended on bilayer composition. The release of PTU from all niosomal formulations studied was retarded and followed the first-order kinetics. Degree of slow release had a negative correlation with drug entrapment. The release rate also depended on the physical state of the bilayer. The results of this study indicate that PTU niosomes were able to control the release of PTU and might be of value to develop further into topical formulations.
Collapse
Affiliation(s)
- Waraporn Suwakul
- Department of Pharmacy, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand
| | | | | |
Collapse
|
10
|
Kisso B, Patel A, Redetzke R, Gerdes AM. Effect of low thyroid function on cardiac structure and function in spontaneously hypertensive heart failure rats. J Card Fail 2008; 14:167-71. [PMID: 18325465 DOI: 10.1016/j.cardfail.2007.10.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2007] [Revised: 10/22/2007] [Accepted: 10/23/2007] [Indexed: 11/15/2022]
Abstract
BACKGROUND Although low thyroid function is known to have detrimental effects on the cardiovascular system, including microvascular impairment, little is known about the pathophysiologic consequences of hypothyroidism in the background of hypertension. METHODS AND RESULTS Hypothyroidism was induced in female spontaneously hypertensive heart failure (SHHF) rats by treatment with propylthiouracil (PTU) for 6 months. Untreated SHHF and normotensive Wistar Furth (WF) rats served as controls. In terminal experiments, heart weight, echocardiographic measurements, hemodynamics, and arteriolar morphometry were performed. Left ventricular internal diameter in systole and diastole were increased and wall thickness, ejection fraction, heart rate, systolic blood pressure, and +/-dP/dt were significantly decreased in the treatment group. Surprisingly, there were no observed differences in arteriolar density among the 3 groups. CONCLUSIONS As expected, PTU treatment of SHHF rats led to systolic dysfunction and chamber dilation. However, PTU treatment did not lead to arteriolar loss as previously observed in normotensive rats treated with PTU. These finding suggest that induced hypothyroidism leads to detrimental changes in SHHF rats, but the overall effects were no worse than those previously observed in normotensive rats treated with PTU.
Collapse
Affiliation(s)
- Bassel Kisso
- Cardiovascular Research Institute, Sanford Research/University of South Dakota, 1100 East 21st Street, Sioux Falls, SD 57105, USA
| | | | | | | |
Collapse
|
11
|
Abstract
Seventy-four pairs of monozygotic (identical) twins and 35 pairs of dizygotic (fraternal) twins provided recognition thresholds (modified Harris-Kalmus test) for the sourness of citric acid and the saltiness of sodium chloride during the Twins Days Festival in Twinsburg, OH. Variance components (ACE) models were applied to the data: total variation = additive genetic (A) + common environment (C) + nonshared environment (E). The best-fit model of variation in recognition thresholds for sourness included an additive genetic factor, accounting for 53% of the variance, but no common environment component. This level of heritability, on par with that of sensitivity to the bitter compounds 6-n-propylthiouracil and phenylthiocarbamide, strongly suggests that genetic factors play a larger role than shared environment in determining individual differences in recognition thresholds for sourness. In contrast, the best-fit model for saltiness recognition included a common environment component, accounting for 22% of the variance in thresholds, but no additive component. This result suggests that environment plays a larger role than genetics in determining individual differences in recognition thresholds for saltiness.
Collapse
Affiliation(s)
- Paul M Wise
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA.
| | | | | | | |
Collapse
|
12
|
Sreejith P, Beyo RS, Divya L, Vijayasree AS, Manju M, Oommen OV. Triiodothyronine and melatonin influence antioxidant defense mechanism in a teleost Anabas testudineus (Bloch): in vitro study. Indian J Biochem Biophys 2007; 44:164-8. [PMID: 17650585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The effect of the hormones triiodothyronine (T3) and melatonin on antioxidant defense system was studied in 6-propyl thiouracil (6-PTU)-treated or photoperiod-exposed teleost Anabas testudineus. 6-PTU (2 microg/g) treatment or photoperiod exposure (24 h) increased malondialdehyde (MDA) and conjugated dienes (CD) concentrations, indicating increased lipid peroxidation (LPO) in the experimental conditions. T3 or melatonin (10(-6) M) treatment for 15 min in vitro in PTU-treated fish reversed the activity of superoxide dismutase (SOD), catalase and glutathione content. T3-treated group showed no change in glutathione peroxidase (GPx) activity, whereas melatonin treatment decreased its activity. T3 inhibited glutathione reductase (GR) activity. Photoperiod exposure (physiological pinealotomy) induced a stressful situation in this teleost, as evidenced by LPO products and antioxidant enzyme activities. Melatonin and T3 treatment for 15 min in vitro also reversed the effect of photoperiod on peroxidation products and the SOD and catalase activities. GR activity decreased in photoperiod-exposed group and melatonin and T3 treatment reversed the activities. The antioxidant enzymes responded to the stress situation after 6-PTU treatment and photoperiod exposure by altering their activities. The study suggested an independent effect of T3 and melatonin on antioxidant defence mechanism in different physiological situations in fish.
Collapse
Affiliation(s)
- P Sreejith
- Department of Zoology, University of Kerala, Kariavattom, Thiruvananthapuram- 695 581, Kerala, India
| | | | | | | | | | | |
Collapse
|
13
|
Antoniadis CD, Hadjikakou SK, Hadjiliadis N, Papakyriakou A, Baril M, Butler IS. Synthesis and Structures of Se Analogues of the Antithyroid Drug 6-n-Propyl-2-thiouracil and Its Alkyl Derivatives: Formation of Dimeric Se–Se Compounds and Deselenation Reactions of Charge-Transfer Adducts of Diiodine. Chemistry 2006; 12:6888-97. [PMID: 16773663 DOI: 10.1002/chem.200501455] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Four selenium analogues of the antithyroid drug 6-n-propyl-2-thiouracil (PTU), of formulae RSeU, (R = methyl (Me) (1), ethyl (Et) (2), n-propyl (nPr) (3), and isopropyl (iPr) 4), have been synthesized. Reaction of 1-4 with diiodine in a 1:1 molar ratio in dichloromethane results in the formation of [(RSeU)I(2)] (R = methyl (5), ethyl (6), n-propyl (7) and isopropyl (8)). All compounds have been characterized by elemental analysis, FT-Raman, FT-IR, UV/Vis, (1)H-, (13)C-, (77)Se-1D and -2D NMR spectroscopy, and ESI-MS spectrometric techniques. Recrystallization of 4 from dichloromethane afforded (4CH(2)Cl(2)). Crystals of [(nPrSeU)I(2)] (7), a charge-transfer complex, were obtained from chloroform solutions, while crystallization of 6 and 7 from acetone afforded the diselenides [N-(6-Et-4-pyrimidone)(6-EtSeU)(2)] (92 H(2)O) and [N-(6-nPr-4-pyrimidone)(6-nPrSeU)(2)] (10) as oxidation products. Recrystallization of 7 from methanol/acetonitrile solutions led to deselenation with the formation of 6-n-propyl-2-uracil (nPrU) (11). [(nPrSeU)I(2)] (7) was found to be a charge-transfer complex with a Se--I bond. These results are discussed in relation to the mechanism of action of antithyroid drugs.
Collapse
Affiliation(s)
- Constantinos D Antoniadis
- Section of Inorganic and Analytical Chemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece
| | | | | | | | | | | |
Collapse
|
14
|
Antoniadis CD, Blake AJ, Hadjikakou SK, Hadjiliadis N, Hubberstey P, Schröder M, Wilson C. Structural characterization of selenium and selenium-diiodine analogues of the antithyroid drug 6-n-propyl-2-thiouracil and its alkyl derivatives. Acta Crystallogr B Struct Sci 2006; 62:580-91. [PMID: 16840807 DOI: 10.1107/s0108768106011426] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2006] [Accepted: 03/29/2006] [Indexed: 11/10/2022]
Abstract
The structures of four selenium analogues of the antithyroid drug 6-n-propyl-2-thiouracil [systematic name: 2,3-dihydro-6-n-propyl-2-thioxopyrimidin-4(1H)-one], namely 6-methyl-2-selenouracil, C5H6N2OSe (1), 6-ethyl-2-selenouracil, C6H8N2OSe (2), 6-n-propyl-2-selenouracil, C7H10N2OSe (3), and 6-isopropyl-2-selenouracil, C7H10N2OSe (4), are described, along with that of the dichloromethane monosolvate of 6-isopropyl-2-selenouracil, C7H10N2OSe·CH2Cl2 (4·CH2Cl2). The extended structure of (1) is a two-dimensional sheet of topology 63 with a brick-wall architecture. The extended structures of (2) and (4) are analogous, being based on a chain of eight-membered R
8
6(32) hydrogen-bonded rings. In (3) and (4·CH2Cl2), R
2
2(8) hydrogen bonding links molecules into chains. 6-n-Propyl-2-selenouracil·I2, C7H10N2OSe·I2 (7), is a charge-transfer complex with a `spoke' structure, the extended structure of which is based on a linear chain formed principally by intermolecular N—H...O hydrogen bonds. Re-crystallization of 6-ethyl-2-selenouracil or (7) from acetone gave crystals of the diselenides [N-(6′-ethyl-4′-pyrimidone)(6-ethyl-2-selenouracil)2(Se—Se)]·2H2O (9·2H2O) or [N-(6′-n-propyl-4′-pyrimidone)(6-n-propyl-2-selenouracil)2(Se—Se)] (10), respectively: these have similar extended chain structures formed via N—H...O and C—H...O hydrogen bonds, stacked to give two-dimensional sheets. Re-crystallization of (7) from methanol/acetonitrile led via deselenation to the formation of crystals of 6-n-propyl-2-uracil (11), in which six symmetry-related molecules combine to form a six-membered R
6
6(24) hydrogen-bonded ring, with each pair of molecules linked by an R
2
2(8) motif.
Collapse
Affiliation(s)
- Constantinos D Antoniadis
- Section of Inorganic and Analytical Chemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece
| | | | | | | | | | | | | |
Collapse
|
15
|
Hansen JL, Reed DR, Wright MJ, Martin NG, Breslin PAS. Heritability and genetic covariation of sensitivity to PROP, SOA, quinine HCl, and caffeine. Chem Senses 2006; 31:403-13. [PMID: 16527870 PMCID: PMC1475779 DOI: 10.1093/chemse/bjj044] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The perceived bitterness intensity for bitter solutions of propylthiouracil (PROP), sucrose octa-acetate (SOA), quinine HCl and caffeine were examined in a genetically informative sample of 392 females and 313 males (mean age of 17.8 +/- 3.1 years), including 62 monozygotic and 131 dizygotic twin pairs and 237 sib pairs. Broad-sense heritabilities were estimated at 0.72, 0.28, 0.34, and 0.30 for PROP, SOA, quinine, and caffeine, respectively, for perceived intensity measures. Modeling showed 1) a group factor which explained a large amount of the genetic variation in SOA, quinine, and caffeine (22-28% phenotypic variation), 2) a factor responsible for all the genetic variation in PROP (72% phenotypic variation), which only accounted for 1% and 2% of the phenotypic variation in SOA and caffeine, respectively, and 3) a modest specific genetic factor for quinine (12% phenotypic variation). Unique environmental influences for all four compounds were due to a single factor responsible for 7-22% of phenotypic variation. The results suggest that the perception of PROP and the perception of SOA, quinine, and caffeine are influenced by two distinct sets of genes.
Collapse
Affiliation(s)
- Jonathan L Hansen
- Genetic Epidemiology Group, Queensland Institute of Medical Research, Brisbane, Australia.
| | | | | | | | | |
Collapse
|
16
|
Abstract
The aims of the present study were to contrast the prevalence of dental caries in children with different genetic sensitivity levels to the bitter taste of 6-n-propylthiouracil (PROP) and to determine the taste quality and taste intensity preferences of food products among the taster and nontaster groups. Overall caries experience (dmfs/DMFS) was significantly higher for nontasters than tasters. Caries experience on the available surfaces (dfs/DFS) was found to be significantly higher in nontasters than in medium tasters and in medium tasters than in supertasters (r=-0.41, P < 0.001). Majority of the nontasters were sweet likers and preferred strong tasting food products, while majority of the supertasters were sweet dislikers and preferred weak tastes. There was a significant increase in the overall caries experience in the population, as the genetic ability to detect PROP taste decreased ( P < 0.001). After all associated factors (age, gender, race, number of teeth and OHI-S) were controlled; multiple linear regression analyses revealed that taste was the only variable significantly related to overall caries experience.
Collapse
Affiliation(s)
- S Rupesh
- Department of Pedodontics and Preventive Dentistry, Rajah Muthiah Dental College and Hospital, Annamalai University, Tamil Nadu, India
| | | |
Collapse
|
17
|
Propylthiouracil. Rep Carcinog 2004; 11:III227-8. [PMID: 21089953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
|
18
|
Barzegar M, Rahmani A, Jabbari A, Mousavi MF. Kinetic-spectrophotometric determination of propylthiouracil based on its inhibitory effect on the reduction of neutral red by hypophosphite. Pharmazie 2003; 58:114-6. [PMID: 12641327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
A new kinetic-spectrophotometric method for determination of propylthiouracil (PTU) is described. The proposed method is simple, rapid, inexpensive and sensitive for the determination of PTU in pure and tablet forms. This method is based on the inhibitory effect of propylthiouracil on the palladium(II)-catalyzed reaction between neutral red and hypophosphite ions. The effect of various parameters such as: dye, hypophosphite, and Pd(II) concentrations, pH, ionic strength, and temperature were optimized. Two distinct linear calibration graphs were observed in the ranges 0.006-0.033 (n = 6, r = 0.9991) and 0.033-0.300 ppm (n = 10, r = 0.9980). The variable time method was used. The limit of detection was 0.004 ppm. The proposed method was applied for the determination of propylthiouracil in pure and tablet forms.
Collapse
Affiliation(s)
- M Barzegar
- Department of Food Science and Technology, Tarbiat Modarres University, Tehran, Iran.
| | | | | | | |
Collapse
|
19
|
Lin BPJ. Caries experience in children with various genetic sensitivity levels to the bitter taste of 6-n-propylthiouracil (PROP): a pilot study. Pediatr Dent 2003; 25:37-42. [PMID: 12627700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
PURPOSE The objective of this pilot study was to determine the prevalence of coronal dental caries among children with different genetic sensitivity levels of taste, as determined by 6-n-propylthiouracil (PROP). METHODS Coronal caries and restorations in permanent and primary dentition were evaluated in 150 healthy school-aged children aged 6 to 12 years. A filter paper containing 6-n-propylthiouracil was used to determine each subject's genetic ability to taste bitter and sweet substances. Supertasters perceived stronger tastes from a variety of bitter and sweet substances than both medium tasters and nontasters. The data were analyzed by ANOVA with Duncan's multiple range test, Mantel-Haenszel chi-square, multiple linear regression analyses, and Pearson's coefficient of correlation. RESULTS The nontasters had more mean decayed, missing, and filled surfaces (dfs/DMFS) than tasters. The values of mean decayed and filled surfaces of primary dentition and mean decayed, missing, and filled surfaces of permanent dentition (dfs/DMFS) and mean decayed surfaces of primary dentition and permanent dentition (ds/DS) were significantly higher in nontasters than in medium tasters, and in medium tasters compared with supertasters. After adjusting for missing teeth, the data were expressed as a percentage of the available surfaces, and the significant differences in dfs/DMFS and ds/DS persisted (r = -0.49, P < .001 and r = -0.51, P < .0001 respectively). CONCLUSIONS After all associated factors were controlled, taste was the only independent variable significantly related to overall caries experience. The results of this study suggested an increased prevalence of overall caries experience in nontaster children.
Collapse
Affiliation(s)
- Brent P J Lin
- Department of Pediatric Dentistry, University of Texas Health Science Center, San Antonio, Tex, USA.
| |
Collapse
|
20
|
Abstract
It is generally assumed that the mutual, but asymmetric, suppression of the components in binary taste mixtures is an invariant property of the human psychophysical response to such mixtures. However, taste intensities have been shown to vary as a function of individual differences in sensitivity, indexed by the perceived bitterness of 6-n-propylthiouracil (PROP). To determine if these variations in taste perception influence taste mixture interactions, groups of PROP super-, medium- and non-tasters assessed four binary taste mixtures: sweet-bitter [sucrose/quinine hydrochloride (QHCl)], sweet-sour (sucrose/citric acid), salty-bitter (NaCl/QHCl) and salty-sour (NaCl/citric acid). In each experiment, subjects received factorial combinations of four levels of each of two tastants and rated individual taste intensities and overall mixture intensity. For each taste quality, super-tasters typically gave higher ratings than either medium- or non-tasters, who tended not to differ. There were also group differences in the interactions of the mixtures' components. Super-tasters rated the overall intensity of the mixtures, most likely reflecting integration of the taste components, as greater than medium- and non-tasters, who again showed few differences. In sweet-bitter mixtures, non-tasters failed to show the suppression of sweetness intensity by the highest QHCl concentration that was evident in super- and medium-tasters. These data show that the perception of both tastes and binary taste mixture interactions varies as a function of PROP taster status, but that this may only be evident when three taster groups are clearly distinguished from one another.
Collapse
Affiliation(s)
- J Prescott
- Sensory Science Research Centre, University of Otago, Dunedin, New Zealand Qi Statistics, King's Lynn, Norfolk, UK.
| | | | | |
Collapse
|
21
|
Drewnowski A, Henderson SA, Hann CS, Berg WA, Ruffin MT. Genetic taste markers and preferences for vegetables and fruit of female breast care patients. J Am Diet Assoc 2000; 100:191-7. [PMID: 10670391 DOI: 10.1016/s0002-8223(00)00061-4] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To explore links between genetic responsiveness to the bitter taste of 6-n-propylthiouracil (PROP) and self-reported preferences for vegetables and fruit of female breast care patients. METHODS PROP tasting was defined by detection thresholds and by perceived bitterness and hedonic ratings for PROP solutions. Nontasters, medium tasters, and supertasters were identified by their PROP thresholds and by the ratio of perceived bitterness of PROP to the perceived saltiness of sodium chloride solutions. Subjects rated preferences for vegetables and fruit using 9-point category scales. SUBJECTS/SETTING A clinical sample of 170 patients with newly diagnosed breast cancer and 156 cancer-free control subjects were recruited from the University of Michigan Breast Care Center. STATISTICAL ANALYSES Principal components factor analysis, one-way analyses of variance, and Pearson correlations and chi 2 tests were used to analyze taste and food preference data. RESULTS Genetic responsiveness to PROP was associated with lower acceptance of cruciferous and selected green and raw vegetables (P < .05). Women who reported disliking such foods were medium tasters or supertasters of PROP. Preference ratings for fruit were unrelated to PROP taster status. APPLICATIONS/CONCLUSIONS Women who are PROP tasters may be less likely to comply with dietary strategies for cancer prevention that emphasize consumption of cruciferous vegetables and bitter salad greens. Alternatively, PROP-sensitive women may seek to reduce bitter taste by adding fat, sugar, or salt.
Collapse
Affiliation(s)
- A Drewnowski
- Nutritional Sciences Program, University of Washington, Seattle 98195-3410, USA
| | | | | | | | | |
Collapse
|
22
|
Vargas G, Havel J, Frgalová K. Capillary zone electrophoresis determination of thyreostatic drugs in urine. J Capillary Electrophor 1998; 5:9-12. [PMID: 10327364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
In this work, a new capillary zone electrophoresis (CZE) method has been developed for the analysis of thyreostatic drugs (TD) such as methylthiouracil (MTU), propylthiouracil (PTU), and thiouracil (TU) in urine specimens. An untreated fused-silica capillary tube (75 microns i.d., 57 cm total length, 49.5 cm length to the detector) was used in all of the experiments. Optimal conditions were found using 50 mM borate buffer, pH 7.6, applied voltage 15 kV, 25 degrees C, and 30 sec of hydrodynamic injection. UV detection at 276 nm was employed. Ethylacetate extraction of the compounds was made before the analysis of each urine sample. An electrostacking procedure to increase the sensitivity was applied. The method developed was used for the analysis of several thousands of samples as part of a veterinary control procedure (Institute for State Control of Veterinary Biological and Medicaments, Brno, Czech Republic). The following detection limits were reached: 0.3 ppm (PTU and MTU) and 0.5 ppm (TU). The standard deviation for PTU, MTU, and TU determination was 1.12, 0.98, and 3.8% rel., respectively.
Collapse
Affiliation(s)
- G Vargas
- Department of Analytical Chemistry, Faculty of Sciences, Masaryk University, Brno, Czech Republic
| | | | | |
Collapse
|
23
|
Abstract
Genetically mediated sensitivity to the bitter taste of 6-n-propylthiouracil (PROP) has been associated with greater acuity for bitter and for some sweet tastes. Thus far, few studies have explored the relationship between PROP taste sensitivity and hedonic responses to bitter and sweet. In this study, 87 normal-weight young women were divided into PROP non-tasters (n = 18), regular tasters (n = 49), and supertasters (n = 20), based on their PROP detection thresholds and the scaling of five suprathreshold solutions of PROP and NaCl. Non-tasters had thresholds > 1.8 x 10(-4) mol/l PROP. Supertasters had thresholds < 3.2 x 10(-5) mol/l PROP and PROP/NaCl ratios > 1.70. As expected, dislike of the bitter taste of PROP was determined by its perceived intensity, which was greater among supertasters than among regular tasters or non-tasters. Significant correlations were observed between PROP taste thresholds and the sum of intensity ratings (r = -0.61) and between summed intensity and summed hedonic ratings (r = -0.80). PROP taste sensitivity was weakly linked to enhanced perception of sweet taste, but did not predict hedonic responses to sucrose or to saccharin solutions. Given that the dislike of PROP solutions is determined by their perceived intensity, hedonic responses to PROP solutions may provide a rapid way of screening for PROP taster status.
Collapse
Affiliation(s)
- A Drewnowski
- Human Nutrition Program, School of Public Health, University of Michigan, Ann Arbor 48109-2029, USA
| | | | | |
Collapse
|
24
|
Gayathri Devi A, Henderson SA, Drewnowski A. Sensory acceptance of Japanese green tea and soy products is linked to genetic sensitivity to 6-n-propylthiouracil. Nutr Cancer 1997; 29:146-51. [PMID: 9427978 DOI: 10.1080/01635589709514616] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Genetic sensitivity to 6-n-propylthiouracil (PROP), a heritable trait, has been linked to increased sensitivity to and increased dislike of other bitter compounds. Many phytochemicals with reputed chemopreventive activity have a bitter taste. This study tested the hypothesis that PROP-sensitive women would be more likely to reject Japanese green tea and selected soy products. Both foods contain bitter flavonoids that are thought to be useful in cancer prevention and control. Study subjects, 53 normal-weight, healthy young women, were divided into PROP nontasters (n = 14), regular tasters (n = 28), and supertasters (n = 11) on the basis of their PROP detection thresholds and mean response ratios to PROP compared with NaCl solutions. The subjects tasted a range of soy products, including tofu, miso, plain soymilk, vanilla-flavored soymilk, and five different concentrations of Japanese green tea. Taste intensity and hedonic preference ratings were measured using nine-point category scales. PROP sensitivity was linked to greater perceived bitterness and increased dislike of Japanese green tea. PROP tasters and supertasters preferred vanilla-flavored soymilk over other soy products. Genetic taste markers may alter dietary exposure to substances thought to affect cancer risk.
Collapse
Affiliation(s)
- A Gayathri Devi
- Human Nutrition Program, School of Public Health, University of Michigan, Ann Arbor 48109, USA
| | | | | |
Collapse
|
25
|
Abstract
Propylthiouracil (PTU) has been demonstrated to reduce alcohol-induced hepatocyte damage and severe alcoholic liver disease. Although the mechanism by which the drug operates is yet to be elucidated, there is evidence that PTU may act as an antioxidant. The present study examines the reaction of PTU with oxygen free radicals and the ability of PTU to directly inhibit peroxidation of a model membrane system. PTU reacted directly with hydroxyl radicals produced by gamma-radiolysis. The rate constant for the PTU/hydroxyl radical reaction as determined by steady state competition kinetics with p-nitrosodimethylaniline was 8 x 10(9) L/mol/sec. PTU was less reactive towards superoxide generated by the xanthine/xanthine oxidase system, having a small but significant inhibitory effect on superoxide-induced reduction of cytochrome c only at a concentration of 200 microM. The ability of PTU to protect lipids from peroxidative changes was tested in membranes prepared from linoleic acid. The rate of peroxidation induced by 40 degrees heat decreased from 0.078 to 0.024 mM hydroperoxide/hr in the presence of 0-50 microM PTU. However, this trend was reversed at PTU concentrations above 50 microM. These data suggest that the protective effects of PTU against liver damage may be due to scavenging reactions with hydroxyl radicals in particular and/or its antioxidant potential.
Collapse
Affiliation(s)
- M Hicks
- Department of Clinical Pharmacology and Toxicology, St Vincent's Hospital, Darlinghurst, New South Wales, Australia
| | | | | |
Collapse
|
26
|
Fauré M, Lissi EA, Videla LA. Evaluation of the antioxidant properties of thyroid hormones and propylthiouracil in the brain-homogenate autoxidation system and in the free radical-mediated oxidation of erythrocyte membranes. Chem Biol Interact 1991; 77:173-85. [PMID: 1991336 DOI: 10.1016/0009-2797(91)90072-f] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The antioxidant capacity of thyroid hormones and the antithyroid drug propylthiouracil was studied in three model systems, namely, autoxidation of rat brain homogenates and oxidation of rat erythrocyte plasma membranes (EPM) induced by either 2,2'-azobis-(2-amidinopropane) (AAP) thermolysis or by gamma irradiation. Thyroid hormones significantly inhibited the development of lipid peroxidation in these systems at micromolar concentrations, as assessed either by visible light emission, thiobarbituric acid reactive substances accumulation or oxygen uptake. This behaviour was not observed when L-3,3',5-triiodothyronine (T3) and L-thyroxine (T4) were assayed at nanomolar concentrations. In EPM exposed to AAP or gamma irradiation, propylthiouracil inhibited the induced lipid peroxidation, with Q1/2 values of 112-150 microM. It is concluded that the antioxidant capacity of thyroid hormones found in vitro may not be of relevance in physiological conditions, which exhibit variations of T3 and T4 levels in the nanomolar range. On the other hand, the behaviour of propylthiouracil as an inhibitor of EPM lipid peroxidation is observed at concentrations close to the therapeutic levels, thus representing a possible complementary action to its antithyroid activity.
Collapse
Affiliation(s)
- M Fauré
- Departamento de Química, Facultad de Ciencia, Universidad de Santiago, Chile
| | | | | |
Collapse
|