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Pujia R, Mazza E, Montalcini T, Arturi F, Brunetti A, Aversa A, Romeo S, Perticone M, Sciacqua A, Pujia A. Liver Stiffness in Obese Hypothyroid Patients Taking Levothyroxine. MEDICINA (KAUNAS, LITHUANIA) 2022; 58:medicina58070946. [PMID: 35888665 PMCID: PMC9316150 DOI: 10.3390/medicina58070946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 07/13/2022] [Accepted: 07/15/2022] [Indexed: 11/16/2022]
Abstract
Background and Objectives: Thyroid dysfunction is associated with non-alcoholic fatty liver disease, but its role in the progression of liver damage in obese patients remains unclear. In addition, several case reports have suggested the existence of a levothyroxine-induced liver injury, which has been poorly investigated. Our aim was to verify whether a difference in the prevalence of liver fibrosis exists in a population of obese individuals taking Levothyroxine. Materials and Methods: We conducted a cross-sectional study on a population of 137 obese individuals, of which 49 were on replacement therapy with Levothyroxine. We excluded those who had hypertriglyceridemia and diabetes mellitus. All participants underwent a liver stiffness assessment by transient elastography as well as biochemical measurements. In subjects with liver fibrosis, other cause of liver fibrosis were ruled out. Results: Participants taking Levothyroxine had a higher prevalence of liver fibrosis than those not taking Levothyroxine (30.6% vs. 2.3%; p < 0.001), and these results were obtained after we made an adjustment for age (Exp(B) = 18.9; 95% CI = 4.1−87.4; p < 0.001). The liver stiffness value differed significantly between groups (6.0 ± 3.6 and 5.1 ± 1.2, p = 0.033). Of those subjects taking Levothyroxine, there were no significant differences in the dose of medication (1.21 ± 0.36 vs. 1.07 ± 0.42; p = 0.240) and treatment duration (13.7 ± 7.43 vs. 11.13 ± 6.23; p = 0.380) between those with and without liver fibrosis. Conclusions: We found, for the first time, a greater prevalence of liver fibrosis in obese individuals taking Levothyroxine than in those not taking this medication. This finding needs to be confirmed by longitudinal population studies as well as by cellular studies.
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Affiliation(s)
- Roberta Pujia
- Department of Medical and Surgical Science, University Magna Grecia of Catanzaro, 88100 Catanzaro, Italy; (R.P.); (E.M.); (F.A.); (S.R.); (M.P.); (A.S.); (A.P.)
| | - Elisa Mazza
- Department of Medical and Surgical Science, University Magna Grecia of Catanzaro, 88100 Catanzaro, Italy; (R.P.); (E.M.); (F.A.); (S.R.); (M.P.); (A.S.); (A.P.)
| | - Tiziana Montalcini
- Department of Clinical and Experimental Medicine, University Magna Grecia of Catanzaro, 88100 Catanzaro, Italy;
- Correspondence:
| | - Franco Arturi
- Department of Medical and Surgical Science, University Magna Grecia of Catanzaro, 88100 Catanzaro, Italy; (R.P.); (E.M.); (F.A.); (S.R.); (M.P.); (A.S.); (A.P.)
| | - Antonio Brunetti
- Department of Health Science, University Magna Grecia of Catanzaro, 88100 Catanzaro, Italy;
| | - Antonio Aversa
- Department of Clinical and Experimental Medicine, University Magna Grecia of Catanzaro, 88100 Catanzaro, Italy;
| | - Stefano Romeo
- Department of Medical and Surgical Science, University Magna Grecia of Catanzaro, 88100 Catanzaro, Italy; (R.P.); (E.M.); (F.A.); (S.R.); (M.P.); (A.S.); (A.P.)
- Department of Molecular and Clinical Medicine, The University of Gothenburg, 40530 Gothenburg, Sweden
| | - Maria Perticone
- Department of Medical and Surgical Science, University Magna Grecia of Catanzaro, 88100 Catanzaro, Italy; (R.P.); (E.M.); (F.A.); (S.R.); (M.P.); (A.S.); (A.P.)
| | - Angela Sciacqua
- Department of Medical and Surgical Science, University Magna Grecia of Catanzaro, 88100 Catanzaro, Italy; (R.P.); (E.M.); (F.A.); (S.R.); (M.P.); (A.S.); (A.P.)
| | - Arturo Pujia
- Department of Medical and Surgical Science, University Magna Grecia of Catanzaro, 88100 Catanzaro, Italy; (R.P.); (E.M.); (F.A.); (S.R.); (M.P.); (A.S.); (A.P.)
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Chlorella sorokiniana Dietary Supplementation Increases Antioxidant Capacities and Reduces Ros Release in Mitochondria of Hyperthyroid Rat Liver. Antioxidants (Basel) 2020; 9:antiox9090883. [PMID: 32957734 PMCID: PMC7555375 DOI: 10.3390/antiox9090883] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 09/02/2020] [Accepted: 09/15/2020] [Indexed: 01/06/2023] Open
Abstract
The ability of aerobic organisms to cope with the attack of radicals and other reactive oxygen species improves by feeding on foods containing antioxidants. Microalgae contain many molecules showing in vitro antioxidant capacity, and their food consumption can protect cells from oxidative insults. We evaluated the capacity of dietary supplementation with 1% dried Chlorella sorokiniana strain 211/8k, an alga rich in glutathione, α-tocopherol, and carotenoids, to counteract an oxidative attack in vivo. We used the hyperthyroid rat as a model of oxidative stress, in which the increase in metabolic capacities is associated with an increase in the release of mitochondrial reactive oxygen species (ROS) and the susceptibility to oxidative insult. Chlorella sorokiniana supplementation prevents the increases in oxidative stress markers and basal oxygen consumption in hyperthyroid rat livers. It also mitigates the thyroid hormone-induced increase in maximal aerobic capacities, the mitochondrial ROS release, and the susceptibility to oxidative stress. Finally, alga influences the thyroid hormone-induced changes in the factors involved in mitochondrial biogenesis peroxisomal proliferator-activated receptor-γ coactivator (PGC1-1) and nuclear respiratory factor 2 (NRF-2). Our results suggest that Chlorella sorokiniana dietary supplementation has beneficial effects in counteracting oxidative stress and that it works primarily by preserving mitochondrial function. Thus, it can be useful in preventing dysfunctions in which mitochondrial oxidative damage and ROS production play a putative role.
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Venditti P, Napolitano G, Fasciolo G, Di Meo S. Thyroid state affects H 2O 2 removal by rat heart mitochondria. Arch Biochem Biophys 2019; 662:61-67. [PMID: 30508506 DOI: 10.1016/j.abb.2018.11.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 11/20/2018] [Accepted: 11/27/2018] [Indexed: 10/27/2022]
Abstract
We investigated the effects of thyroid state on the mechanisms underlying rat heart mitochondrial capacity to remove H2O2 produced by an exogenous source. The removal rates were higher in the presence of respiratory substrates independently from thyroid state and were higher in hyperthyroid than in hypothyroid preparations. The thyroid state-linked changes in H2O2 removal rates, mirrored those in H2O2 release rates, showing that endogenous and exogenous H2O2 do not compete for the removing system. Mitochondrial content of coenzyme Q9 and Q10 was lower in hypothyroidism and higher in hyperthyroidism suggesting that the thyroid state-linked changes in the rates of H2O2 production are due to changes in the ubiquinone mitochondrial content. The rates of H2O2 removal in the presence of antioxidant enzyme inhibitors indicated that the contribution of each antioxidant is dependent on the thyroid state. This was supported by enzymatic activity measurements. Pharmacological inhibition also showed that the overall percentage contribution of the enzymatic processes, as well as that of non-enzymatic processes, is not affected by thyroid state. Cytochrome levels, inferred by light emission measurements, and western blot determination of cytochrome c, were lower in hypothyroid and higher in hyperthyroid preparations supporting the idea that the levels of reducing compounds were modified in opposite way by the changes in thyroid state. Further support was obtained showing that the whole antioxidant capacity, which provides an evaluation of capacity of the systems, different from cytochromes, assigned to H2O2 scavenging, was lower in hyperthyroid than in hypothyroid state.
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Affiliation(s)
- Paola Venditti
- Dipartimento di Biologia, Università di Napoli Federico II, I-80126, Napoli, Italy.
| | - Gaetana Napolitano
- Dipartimento di Biologia, Università di Napoli Federico II, I-80126, Napoli, Italy
| | - Gianluca Fasciolo
- Dipartimento di Biologia, Università di Napoli Federico II, I-80126, Napoli, Italy
| | - Sergio Di Meo
- Dipartimento di Biologia, Università di Napoli Federico II, I-80126, Napoli, Italy
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Napolitano G, Barone D, Di Meo S, Venditti P. Adrenaline induces mitochondrial biogenesis in rat liver. J Bioenerg Biomembr 2017; 50:11-19. [PMID: 29243009 DOI: 10.1007/s10863-017-9736-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 11/21/2017] [Indexed: 12/01/2022]
Abstract
We studied the effects of adrenaline administration and depletion (induced by reserpine) on rat liver oxidative metabolism. We showed that adrenaline increases, and reserpine decreases aerobic capacity (inferred by cytochrome oxidase activity) in tissue modifying the hepatic content of mitochondrial proteins without changing mitochondrial aerobic capacity. The changes in tissue cytochrome oxidase activity, which agreed with the expression levels of factors involved in mitochondrial biogenesis, such as PGC-1, NRF-1, and NRF-2, were associated with similar changes in tissue and mitochondrial State 3 respiration. Adrenaline and reserpine induced extensive lipid and protein oxidative damage in tissue and mitochondria. The increase in H2O2 release by respiring mitochondria and the decrease in the activities of the antioxidant enzymes glutathione peroxidase and reductase contributed to the reserpine effect on oxidative damage. The adrenaline effect is more difficult to explain, since the hormone increased the antioxidant enzyme activities but, in respiring mitochondria, increased ROS release rate in the presence of succinate and decreased it in the presence of pyruvate/malate. These opposite changes were due to the increased content of the autoxidizable electron carrier located at complex III and decreased content of that located at complex I. Our data suggest that adrenaline can be involved in the mitochondrial population adaptation which verify in conditions in which an increased body energy expenditure verify such as cold exposure.
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Affiliation(s)
- Gaetana Napolitano
- Department of Biology, University of Naples "Federico II", Complesso Universitario Monte Sant'Angelo, Via Cinthia, I-80126, Naples, Italy
| | - Daniela Barone
- Department of Biology, University of Naples "Federico II", Complesso Universitario Monte Sant'Angelo, Via Cinthia, I-80126, Naples, Italy
| | - Sergio Di Meo
- Department of Biology, University of Naples "Federico II", Complesso Universitario Monte Sant'Angelo, Via Cinthia, I-80126, Naples, Italy
| | - Paola Venditti
- Department of Biology, University of Naples "Federico II", Complesso Universitario Monte Sant'Angelo, Via Cinthia, I-80126, Naples, Italy.
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Venditti P, Bari A, Di Stefano L, Cardone A, Della Ragione F, D'Esposito M, Di Meo S. Involvement of PGC-1, NRF-1, and NRF-2 in metabolic response by rat liver to hormonal and environmental signals. Mol Cell Endocrinol 2009; 305:22-9. [PMID: 19433258 DOI: 10.1016/j.mce.2009.02.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Revised: 01/28/2009] [Accepted: 02/12/2009] [Indexed: 10/21/2022]
Abstract
We studied liver oxidative capacity and O2 consumption in hypothyroid rats treated for 10 days with T4, or T3, or treated for 10 days with T3 and exposed to cold for the last 2 days. The metabolic response of homogenates and mitochondria indicated that all treatments increased the synthesis of respiratory chain components, whereas only the cold-induced mitochondrial proliferation. Determination of mRNA and protein expression of transcription factor activators, such as NRF-1 and NRF-2, and coactivators, such as PGC-1, showed that mRNA levels, except PGC-1 ones, were not related to aerobic capacities. Conversely, a strong correlation was found between cytochrome oxidase activity and PGC-1 or NRF-2 protein levels. Such a correlation was not found for NRF-1. Our results strongly support the view that in rat liver PGC-1 and NRFs are responsible for the iodothyronine-induced increases in respiratory chain components, whereas their role in cold-induced mitochondrial proliferation needs to be further on clarified.
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Affiliation(s)
- P Venditti
- Dipartimento delle Scienze Biologiche, Sezione di Fisiologia, Università di Napoli Federico II, Via Mezzocannone 8, I-80134 Napoli, Italy.
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Venditti P, Bari A, Di Stefano L, Di Meo S. Vitamin E attenuates cold-induced rat liver oxidative damage reducing H2O2 mitochondrial release. Int J Biochem Cell Biol 2007; 39:1731-42. [PMID: 17553729 DOI: 10.1016/j.biocel.2007.04.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Revised: 04/18/2007] [Accepted: 04/25/2007] [Indexed: 11/25/2022]
Abstract
Vitamin E is a major chain-breaking antioxidant which is able to reduce liver oxidative damage without modifying aerobic capacity in T(3)-treated rats. We investigated whether vitamin E has similar effects in hyperthyroid state induced by cold exposure. Cold exposure increased aerobic capacity and O(2) consumption in homogenates and mitochondria and tissue mitochondrial protein content. Vitamin E did not modify aerobic capacity and mitochondrial protein content of cold liver, but increased ADP-stimulated respiration of liver preparations. Succinate-supported H(2)O(2) release rates were increased by cold during basal and stimulated respiration, whereas the pyruvate/malate-supported ones increased only during basal respiration. Vitamin administration to cold-exposed rats decreased H(2)O(2) release rates with both substrates during basal respiration. This effect reduced ROS flow from mitochondria to cytosol, limiting liver oxidative damage. Cold exposure also increased mitochondrial capacity to remove H(2)O(2), which was reduced by vitamin treatment, showing that the antioxidant also lowers H(2)O(2) production rate. The different effects of cold exposure and vitamin treatment on H(2)O(2) generation were also found in the presence of respiration inhibitors. Although this can suggest that the cold and vitamin induce opposite changes in mitochondrial content of autoxidizable electron carriers, it is likely that vitamin effect is due to its capacity to scavenge superoxide radical. Finally, vitamin E reduced mitochondrial oxidative damage and susceptibility to oxidants, and prevented Ca(2+)-induced swelling elicited by cold. In the whole, our results suggest that vitamin E is able to maintain aerobic capacity and attenuate oxidative stress of hepatic tissue in cold-exposed rats modifying mitochondrial population characteristics.
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Affiliation(s)
- P Venditti
- Dipartimento delle Scienze Biologiche, Sezione di Fisiologia, Università di Napoli, I-80134 Napoli, Italy.
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Justo R, Oliver J, Gianotti M. Brown adipose tissue mitochondrial subpopulations show different morphological and thermogenic characteristics. Mitochondrion 2005; 5:45-53. [PMID: 16075478 DOI: 10.1016/j.mito.2004.09.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Rat brown adipose tissue mitochondrial subpopulations-isolated by differential centrifugation at 1000, 3000 and 8000g, giving the heavy, medium and light mitochondria-were characterized. Thus, contamination by non-mitochondrial subcellular components, morphological features, respiratory chain and antioxidant enzyme activities, both uncoupling protein 1 and mitochondrial protein content, mitochondrial DNA levels and mitochondrial integrity were measured. Results indicate that mitochondrial fractions showed important differences in the morphological, thermogenic and antioxidant properties. All the parameters studied were always higher in heavy mitochondria, which is indicative of a greater mitochondrial differentiation state.
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Affiliation(s)
- Roberto Justo
- Departament de Biologia Fonamental i Ciències de la Salut, Institut Universitari d'lnvestigacióen Ciències de la Salut (IUNICS), Universitat de les Illes Balears, E-07122 Palma de Mallorca, Spain
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Justo R, Boada J, Frontera M, Oliver J, Bermúdez J, Gianotti M. Gender dimorphism in rat liver mitochondrial oxidative metabolism and biogenesis. Am J Physiol Cell Physiol 2005; 289:C372-8. [PMID: 15800054 DOI: 10.1152/ajpcell.00035.2005] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the present study, we have investigated gender differences in rat liver mitochondrial oxidative metabolism. Total mitochondrial population (M) as well as the heavy (M1), medium (M3), and light (M8) mitochondrial fractions obtained by means of differential centrifugation steps at 1,000, 3,000, and 8,000 g, respectively, were isolated. Electron microscopic analysis was performed and mitochondrial protein content and cardiolipin levels, mitochondrial O(2) flux, ATP synthase activity, mitochondrial membrane potential, and mitochondrial transcription factor A (TFAM) protein levels were measured in each sample. Our results indicate that mitochondria from females have higher protein content and higher cardiolipin levels, greater respiratory and phosphorylative capacities, and more-energized mitochondria in respiratory state 3. Moreover, protein levels of TFAM were four times greater in females than in males. Gender differences in the aforementioned parameters were more patent in the isolated heavy M1 and M3 mitochondrial fractions. The present study demonstrates that gender-related differences in liver mitochondrial function are due mainly to a higher capacity and efficiency of substrate oxidation, likely related to greater mitochondrial machinery in females than in males, which is in accord with greater mitochondrial differentiation in females.
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Affiliation(s)
- Roberto Justo
- Grup de Metabolisme Energètic i Nutrició, Departament de Biologia Fonamental i Ciències de la Salut, Institut Universitari d'Investigació en Ciències de la Salut, Universitat de les Illes Balears, Palma de Mallorca, Spain
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Justo R, Frontera M, Pujol E, Rodríguez-Cuenca S, Lladó I, García-Palmer FJ, Roca P, Gianotti M. Gender-related differences in morphology and thermogenic capacity of brown adipose tissue mitochondrial subpopulations. Life Sci 2005; 76:1147-58. [PMID: 15620578 DOI: 10.1016/j.lfs.2004.08.019] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2004] [Accepted: 08/17/2004] [Indexed: 11/23/2022]
Abstract
To investigate the possible existence of a gender dimorphism in the morphology and functionality of brown adipose tissue (BAT) mitochondrial subpopulations, we obtained three mitochondrial fractions - heavy, medium and light - by differential centrifugation. Electron microscopic analysis was carried out and mitochondrial protein content, cytochrome c oxidase and ATP synthase activities, mitochondrial DNA content and UCP1 protein levels were measured in each mitochondrial fraction. Female rats showed a greater mitochondrial size than males, with a different distribution pattern of the subpopulations. These differences were accompanied by higher oxidative and thermogenic capacities and a higher protein content in female rat BAT. This tissue also showed a greater tendency to respiratory chain uncoupling, as well as a close coordination between the oxidative, phosphorylative and thermogenic processes. These differences were found in the heavy subpopulation but not in the light one. Our results demonstrate that female rat BAT shows a highly differentiated mitochondrial pool, with the heavy mitochondrial subpopulation as the main responsible for the greater thermogenic activity of this tissue. In addition, it seems that there is a differential regulation of the mitochondrial growth cycle between genders in BAT, which leads to enhanced thermogenic capacity in female rat mitochondria.
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Affiliation(s)
- Roberto Justo
- Departament de Biologia Fonamental i Ciències de la Salut, Institut Universitari d'Investigació en Ciències de la Salut (IUNICS), Universitat de les Illes Balears, Cra. Valldemossa km 7.5. E-07122-Palma de Mallorca, Spain
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Short KR, Nygren J, Barazzoni R, Levine J, Nair KS. T(3) increases mitochondrial ATP production in oxidative muscle despite increased expression of UCP2 and -3. Am J Physiol Endocrinol Metab 2001; 280:E761-9. [PMID: 11287359 DOI: 10.1152/ajpendo.2001.280.5.e761] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Triiodothyronine (T(3)) increases O(2) and nutrient flux through mitochondria (Mito) of many tissues, but it is unclear whether ATP synthesis is increased, particularly in different types of skeletal muscle, because variable changes in uncoupling proteins (UCP) and enzymes have been reported. Thus Mito ATP production was measured in oxidative and glycolytic muscles, as well as in liver and heart, in rats administered T(3) for 14 days. Relative to saline-treated controls, T(3) rats had 80, 168, and 62% higher ATP production in soleus muscle, liver, and heart, respectively, as well as higher activities of citrate synthase (CS; 63, 90, 25%) and cytochrome c oxidase (COX; 119, 225, 52%) in the same tissues (all P < 0.01). In plantaris muscle of T(3) rats, CS was only slightly higher (17%, P < 0.05) than in controls, and ATP production and COX were unaffected. mRNA levels of COX I and III were 33 and 47% higher in soleus of T(3) rats (P < 0.01), but there were no differences in plantaris. In contrast, UCP2 and -3 mRNAs were 2.5- to 14-fold higher, and protein levels were 3- to 10-fold higher in both plantaris and soleus of the T(3) group. We conclude that T(3) increases oxidative enzymes and Mito ATP production and Mito-encoded transcripts in oxidative but not glycolytic rodent tissues. Despite large increases in UCP expression, ATP production was enhanced in oxidative tissues and maintained in glycolytic muscle of hyperthyroid rats.
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Affiliation(s)
- K R Short
- Endocrinology Research Unit, Mayo Clinic, Rochester, Minnesota 55905, USA
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Donahue RJ, Razmara M, Hoek JB, Knudsen TB. Direct influence of the p53 tumor suppressor on mitochondrial biogenesis and function. FASEB J 2001; 15:635-44. [PMID: 11259382 DOI: 10.1096/fj.00-0262com] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Mitochondrial localization of p53 has been observed in several cell systems, but an understanding of its organelle-based physiological activity remains incomplete. The purpose of the present study was to investigate the mitochondrial DNA genomic response to dominant-negative p53 mutant miniprotein (p53DD) fused to a mitochondrial import signal. Constructs were generated to express mitochondrial targeted enhanced green fluorescent protein (mEGFP) or dominant-negative mutant p53 miniprotein (m53DD) by in-frame fusion to the signal peptide sequence of murine Cox8l. Control cytosolic vectors (cEGFP, c53DD) had the signal sequence placed in antisense orientation. NIH 3T3 cells were transiently transfected with these vectors in various combinations. Mitochondrial 16S ribosomal RNA (16S rRNA) expression and fluorochrome staining with Mitotracker Red CMXRos (DeltaPsim) were decreased in cells expressing m53DD. Both alterations were specific for mitochondrial import competence (e.g., m53DD vs. c53DD) as well as the passenger protein (e.g., m53DD vs. mEGFP). The normal functional state of mitochondria was restored with PK11195, a specific ligand of the mitochondrial peripheral-type benzodiazepine receptor. Negative dominance of m53DD on 16S rRNA expression and CMXRos staining, and rescue of these parameters with PK11195, imply a direct positive effect of p53 on mitochondrial biogenesis and function.
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Affiliation(s)
- R J Donahue
- Department of Pathology, Anatomy and Cell Biology, Jefferson Medical College, Philadelphia, Pennsylvania 19107, USA
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Abstract
Thyroid hormones exert profound effects on the energy metabolism. An inspection of the early and more recent literature shows that several targets at the cellular level have been identified. Since their effects on the nuclear signalling pathway have already been well-defined and extensively reviewed, this article focuses on the regulation of mitochondrial activity by thyroid hormones. Mitochondria, by virtue of their biochemical functions, are a natural candidate as a direct target for the calorigenic effects of thyroid hormones. To judge from results coming from various laboratories, it is quite conceivable that mitochondrial activities are regulated both directly and indirectly. Not only triiodo-L-thyronine, but also diiodothyronines are active in regulating the energy metabolism. They influence the resting metabolism in rats with 3,5-diiodo-L-thyronine seeming to show a clearer effect.
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Affiliation(s)
- F Goglia
- Dipartimento di Fisiologia Generale ed Ambientale, Università di Napoli Federico II, Italy. it
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Abstract
The liver has an important role in thyroid hormone metabolism and the level of thyroid hormones is also important to normal hepatic function and bilirubin metabolism. Besides the associations between thyroid and liver diseases of an autoimmune nature, such as that between primary biliary cirrhosis and hypothyroidism, thyroid diseases are frequently associated with liver injuries or biochemical test abnormalities. For example, thyroid diseases may be associated with elevation of alanine aminotransferase and alkaline phosphatase, which is mainly of bone origin, in hyperthyroidism and aspartate aminotransferase in hypothyroidism. Liver diseases are also frequently associated with thyroid test abnormalities or dysfunctions, particularly elevation of thyroxine-binding globulin and thyroxine. Hepatitis C virus infection has been connected with thyroid abnormalities. In addition, antithyroid drug therapy may result in hepatitis, cholestasis or transient subclinical hepatotoxicity, whereas interferon (IFN) therapy in liver diseases may also induce thyroid dysfunctions. These thyroid-liver associations may cause diagnostic confusions. Neglect of these facts may result in over of under diagnosis of associated liver or thyroid diseases and thereby cause errors in patient care. It is suggested to measure free thyroxine (FT4) and thyroid-stimulating hormone (TSH) which are usually normal in euthyroid patients with liver disease, to rule out or rule in coexistent thyroid dysfunctions, and consider the possibility of thyroid dysfunctions in any patients with unexplained liver biochemical test abnormalities. It is also advisable to monitor patients with autoimmune liver disease or those receiving IFN therapy for the development of thyroid dysfunctions, and patients receiving antithyroid therapy for the development of hepatic injuries.
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Affiliation(s)
- M J Huang
- Division of Endocrinology, Chang Gung Memorial Hospital, Taipei, Taiwan
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Iossa S, Barletta A, Liverini G. The effect of thyroid state and cold exposure on rat liver oxidative phosphorylation. Mol Cell Endocrinol 1991; 75:15-8. [PMID: 2050263 DOI: 10.1016/0303-7207(91)90240-s] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In this paper we have examined the effect of cold exposure on hepatic mitochondrial state 3 respiration and ATP synthesis, using succinate as the substrate, in euthyroid, hypothyroid and hyperthyroid rats. The results show that cold exposure does not elicit any variation in the above parameters in euthyroid and hyperthyroid rats, whereas when hypothyroid rats are exposed to cold, a significant increase (about +45%) occurs in state 3 respiration and ATP synthesis. We have also measured succinic dehydrogenase specific activity and uncoupled respiration during cold exposure in various thyroid states. The finding that cold exposure elicits no variation in the above parameters indicates that there is some control on ATP synthase and/or adenine nucleotide translocator. The above findings, as a whole, suggest that cold exposure acts on oxidative phosphorylation only if triiodothyronine is lacking, by controlling ATP synthase and/or adenine nucleotide translocator.
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Affiliation(s)
- S Iossa
- Department of General and Environmental Physiology, University of Naples, Italy
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