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1.
Inhal Toxicol ; 35(11-12): 300-307, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37995092

RESUMO

OBJECTIVES: The work shows the effect of counting rules, such as analysis magnification and asbestos fiber dimension to be count (with length ≥5 µm or also asbestos fibers with length <5 µm) in the lung asbestos fiber burden analysis for legal medicine evaluations. METHODS: On the same lung tissue samples, two different analyses were carried out to count any asbestos fibers with length ≥1 µm and with length ≥5 µm. Results of the amphibole burden of the two analyses were compared by linear regression analysis on log10-transformed values. RESULTS: The analysis should be carried out at an appropriate magnification and on samples prepared in such a way as they allow the counting of very fine fibers. If the analysis is limited to the asbestos fibers with length ≥5 µm, there is a high risk of not detecting possible residual chrysotile fiber burden and thinner crocidolite asbestos fibers. CONCLUSIONS: On average we estimated that 1 amphibole fiber with length ≥5 µm corresponds to ∼8 amphibole fibers with length ≥1 µm in the lung. The values of the Helsinki criteria should be updated taking this into account.


Assuntos
Amianto , Neoplasias Pulmonares , Humanos , Amianto/toxicidade , Amianto/análise , Pulmão/química , Amiantos Anfibólicos/toxicidade , Amiantos Anfibólicos/análise , Asbestos Serpentinas/toxicidade , Medicina Legal
2.
Biochem J ; 473(16): 2519-30, 2016 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-27287557

RESUMO

ATP synthase, canonically mitochondrially located, is reported to be ectopically expressed on the plasma membrane outer face of several cell types. We analysed, for the first time, the expression and catalytic activities of the ecto- and mitochondrial ATP synthase during liver regeneration. Liver regeneration was induced in rats by two-thirds partial hepatectomy. The protein level and the ATP synthase and/or hydrolase activities of the hepatocyte ecto- and mitochondrial ATP synthase were analysed on freshly isolated hepatocytes and mitochondria from control, sham-operated and partial hepatectomized rats. During the priming phase of liver regeneration, 3 h after partial hepatectomy, liver mitochondria showed a marked lowering of the ATP synthase protein level that was reflected in the impairment of both ATP synthesis and hydrolysis. The ecto-ATP synthase level, in 3 h partial hepatectomized hepatocytes, was decreased similarly to the level of the mitochondrial ATP synthase, associated with a lowering of the ecto-ATP hydrolase activity coupled to proton influx. Noteworthily, the ecto-ATP synthase activity coupled to proton efflux was completely inhibited in 3 h partial hepatectomized hepatocytes, even in the presence of a marked intracellular acidification that would sustain it as in control and sham-operated hepatocytes. At the end of the liver regeneration, 7 days after partial hepatectomy, the level and the catalytic activities of the ecto- and mitochondrial ATP synthase reached the control and sham-operated values. The specific modulation of hepatocyte ecto-ATP synthase catalytic activities during liver regeneration priming phase may modulate the extracellular ADP/ATP levels and/or proton influx/efflux trafficking, making hepatocyte ecto-ATP synthase a candidate for a novel player in the liver regeneration process.


Assuntos
Adenosina Trifosfatases/metabolismo , Regeneração Hepática , Proteínas de Membrana/metabolismo , Animais , Biocatálise , Hepatectomia , Masculino , Mitocôndrias Hepáticas/enzimologia , ATPases Mitocondriais Próton-Translocadoras/metabolismo , Ratos , Ratos Wistar
3.
J Bioenerg Biomembr ; 48(5): 521-529, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27854029

RESUMO

The role of 3,5-diiodo-L-thyronine (T2), initially considered only a 3,3',5-triiodo-L-thyronine (T3) catabolite, in the bioenergetic metabolism is of growing interest. In this study we investigated the acute effects (within 1 h) of T2 administration to hypothyroid rats on liver mitochondria fatty acid uptake and ß-oxidation rate, mitochondrial efficiency (by measuring proton leak) and mitochondrial oxidative damage (by determining H2O2 release). Fatty acid uptake into mitochondria was measured assaying carnitine palmitoyl transferase (CPT) I and II activities, and fatty acid ß-oxidation using palmitoyl-CoA as a respiratory substrate. Mitochondrial fatty acid pattern was defined by gas-liquid chromatography. In hypothyroid + T2 vs hypothyroid rats we observed a raise in the serum level of nonesterified fatty acids (NEFA), in the mitochondrial CPT system activity and in the fatty acid ß-oxidation rate. A parallel increase in the respiratory chain activity, mainly from succinate, occurs. When fatty acids are chelated by bovine serum albumin, a T2-induced increase in both state 3 and state 4 respiration is observed, while, when fatty acids are present, mitochondrial uncoupling occurs together with increased proton leak, responsible for mitochondrial thermogenesis. T2 administration decreases mitochondrial oxidative stress as determined by lower H2O2 production. We conclude that in rat liver mitochondria T2 acutely enhances the rate of fatty acid ß-oxidation, and the activity of the downstream respiratory chain. The T2-induced increase in proton leak may contribute to mitochondrial thermogenesis and to the reduction of oxidative stress. Our results strengthen the previously reported ability of T2 to reduce adiposity, dyslipidemia and to prevent liver steatosis.


Assuntos
Di-Iodotironinas/farmacologia , Metabolismo Energético/efeitos dos fármacos , Hipotireoidismo/tratamento farmacológico , Mitocôndrias Hepáticas/metabolismo , Animais , Di-Iodotironinas/administração & dosagem , Transporte de Elétrons/efeitos dos fármacos , Ácidos Graxos/metabolismo , Oxirredução/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Ratos , Desacopladores/farmacologia
4.
IUBMB Life ; 67(1): 9-17, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25631376

RESUMO

Nonalcoholic fatty liver disease (NAFLD) represents the most common chronic liver disease in western countries, being considered the hepatic manifestation of metabolic syndrome. Cumulative lines of evidence suggest that olive oil, used as primary source of fat by Mediterranean populations, may play a key role in the observed health benefits on NAFLD. In this review, we summarize the state of the art of the knowledge on the protective role of both major and minor components of olive oil on lipid metabolism during NAFLD. In particular, the biochemical mechanisms responsible for the increase or decrease in hepatic lipid content are critically analyzed, taking into account that several studies have often provided different and/or conflicting results in animal models fed on olive oil-enriched diet. In addition, new findings that highlight the hypolipidemic and the antisteatotic actions of olive oil phenols are presented. As mitochondrial dysfunction plays a key role in the pathogenesis of NAFLD, the targeting of these organelles with olive oil phenols as a powerful therapeutic approach is also discussed.


Assuntos
Metabolismo dos Lipídeos/efeitos dos fármacos , Fígado/metabolismo , Hepatopatia Gordurosa não Alcoólica/metabolismo , Azeite de Oliva/química , Fenóis/farmacologia , Humanos , Metabolismo dos Lipídeos/fisiologia , Mitocôndrias/efeitos dos fármacos , Azeite de Oliva/farmacologia
5.
J Hazard Mater ; 476: 134928, 2024 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-38943892

RESUMO

Serpentinite is a widespread rock type used worldwide as building material. Heavy metals like Ni in both the serpentinite products and serpentinite mining wastes pose potential environmental and health issues. This work devises an analytical protocol to identify and quantify the Ni speciation in the mineralogical matrix, through: i) bulk Ni quantification; ii) quantitative mineralogical and chemical analysis of each Ni-rich mineral; iii) comparison of bulk analysis results with the sum of each contribution from the Ni-rich minerals. As case study, two commercial serpentinites "Verde Giada" (VG) and "Verde Vittoria" (VV) from Valmalenco (Northern Italy) were analysed by ICP-MS, XRPD, TGA-MSEGA, SEM, TEM, EPMA, and micro-Raman spectroscopy. The bulk Ni content is 1500-1750 mg/kg and 1390-1620 mg/kg for VG and VV, respectively. The major minerals from XRPD and EPMA (antigorite, olivine, pyroxene, magnetite, brucite) account for 1094 and 1291 mg/kg of Ni for VG and VV, respectively. SEM/TEM and EPMA highlighted the presence of minor chrysotile, pentlandite, heazlewoodite, awaruite, rising the computed Ni to 1924 and 1761 mg/kg for VG and VV, in good agreement with bulk ICP-MS. This protocol provides robust results and can thus enhance the exposure assessment of Ni and eventually other naturally occurring hazardous metals.

6.
R Soc Open Sci ; 9(12): 221022, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36569229

RESUMO

Adult molluscs produce shells with diverse morphologies and ornamentations, different colour patterns and microstructures. The larval shell, however, is a phenotypically more conserved structure. How do developmental and evolutionary processes generate varying diversity at different life-history stages within a species? Using live imaging, histology, scanning electron microscopy and transcriptomic profiling, we have described shell development in a heteroconchian bivalve, the Antarctic clam, Laternula elliptica, and compared it to adult shell secretion processes in the same species. Adult downstream shell genes, such as those encoding extracellular matrix proteins and biomineralization enzymes, were largely not expressed during shell development. Instead, a development-specific downstream gene repertoire was expressed. Upstream regulatory genes such as transcription factors and signalling molecules were largely conserved between developmental and adult shell secretion. Comparing heteroconchian data with recently reported pteriomorphian larval shell development data suggests that, despite being phenotypically more conserved, the downstream effectors constituting the larval shell 'tool-kit' may be as diverse as that of adults. Overall, our new data suggest that a larval shell formed using development-specific downstream effector genes is a conserved and ancestral feature of the bivalve lineage, and possibly more broadly across the molluscs.

7.
Nat Commun ; 13(1): 773, 2022 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-35140205

RESUMO

The transcription factor RUNX1 is a critical regulator of developmental hematopoiesis and is frequently disrupted in leukemia. Runx1 is a large, complex gene that is expressed from two alternative promoters under the spatiotemporal control of multiple hematopoietic enhancers. To dissect the dynamic regulation of Runx1 in hematopoietic development, we analyzed its three-dimensional chromatin conformation in mouse embryonic stem cell (ESC) differentiation cultures. Runx1 resides in a 1.1 Mb topologically associating domain (TAD) demarcated by convergent CTCF motifs. As ESCs differentiate to mesoderm, chromatin accessibility, Runx1 enhancer-promoter (E-P) interactions, and CTCF-CTCF interactions increase in the TAD, along with initiation of Runx1 expression from the P2 promoter. Differentiation to hematopoietic progenitor cells is associated with the formation of tissue-specific sub-TADs over Runx1, a shift in E-P interactions, P1 promoter demethylation, and robust expression from both Runx1 promoters. Deletion of promoter-proximal CTCF sites at the sub-TAD boundaries has no obvious effects on E-P interactions but leads to partial loss of domain structure, mildly affects gene expression, and delays hematopoietic development. Together, our analysis of gene regulation at a large multi-promoter developmental gene reveals that dynamic sub-TAD chromatin boundaries play a role in establishing TAD structure and coordinated gene expression.


Assuntos
Cromatina/metabolismo , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Subunidade alfa 2 de Fator de Ligação ao Core/metabolismo , Expressão Gênica , Animais , Proteínas de Ciclo Celular/metabolismo , Diferenciação Celular , DNA/química , Regulação da Expressão Gênica no Desenvolvimento , Células-Tronco Hematopoéticas/metabolismo , Mesoderma/metabolismo , Camundongos , Conformação de Ácido Nucleico , Regiões Promotoras Genéticas
8.
J Bioenerg Biomembr ; 43(4): 349-57, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21739248

RESUMO

Short-term effects of 3,5-L-diiodothyronine (T(2)) administration to hypothyroid rats on F(o)F(1)-ATP synthase activity were investigated in liver mitochondria. One hour after T(2) injection, state 4 and state 3 respiration rates were noticeably stimulated in mitochondria subsequently isolated. F(o)F(1)-ATP synthase activity, which was reduced in mitochondria from hypothyroid rats as compared to mitochondria from euthyroid rats, was significantly increased by T(2) administration in both the ATP-synthesis and hydrolysis direction. No change in ß-subunit mRNA accumulation and protein amount of the α-ß subunit of F(o)F(1)-ATP synthase was found, ruling out a T(2) genomic effect. In T(2)-treated rats, changes in the composition of mitochondrial phospholipids were observed, cardiolipin (CL) showing the greatest alteration. In mitochondria isolated from hypothyroid rats the decrease in the amount of CL was accompanied by an increase in the level of peroxidised CL. T(2) administration to hypothyroid rats enhanced the level of CL and decreased the amount of peroxidised CL in subsequently isolated mitochondria, tending to restore the CL value to the euthyroid level. Minor T(2)-induced changes in mitochondrial fatty acid composition were detected. Overall, the enhanced F(o)F(1)-ATP synthase activity observed following injection of T(2) to hypothyroid rats may be ascribed, at least in part, to an increased level of mitochondrial CL associated with decreased peroxidation of CL.


Assuntos
Cardiolipinas/metabolismo , Di-Iodotironinas/farmacologia , Hipotireoidismo/metabolismo , Mitocôndrias Hepáticas/efeitos dos fármacos , ATPases Translocadoras de Prótons/metabolismo , Trifosfato de Adenosina/biossíntese , Animais , Hipotireoidismo/tratamento farmacológico , Hipotireoidismo/enzimologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Masculino , Mitocôndrias Hepáticas/enzimologia , Mitocôndrias Hepáticas/metabolismo , Membranas Mitocondriais/efeitos dos fármacos , Membranas Mitocondriais/metabolismo , ATPases Translocadoras de Prótons/biossíntese , ATPases Translocadoras de Prótons/genética , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Ratos , Ratos Wistar
9.
Eur J Surg Oncol ; 47(8): 1847-1855, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33757650

RESUMO

Despite several recent advances, lung cancer surgery is still associated with potentially severe postoperative complications. It has been suggested that preoperative exercise training could render patients with borderline functional parameters eligible for surgery, improve perioperative outcomes and that these benefits might reduce healthcare costs. Nevertheless, given the substantial heterogeneity of the available studies, no specific guidelines for preoperative exercise training have been released so far. This narrative review aims to provide an overview of the potential benefits of exercise training in the preoperative period as a central intervention for lung cancer patients. In detail, the effects of exercise (with different regimens) were evaluated in terms of physical functions, patients' eligibility for curative surgery, postoperative complications and length of stay, with an exploratory focus on healthcare costs and long-term outcomes. Furthermore, a feasible approach for every-day clinical practice is proposed in order to increase the expected benefit deriving from a more extensive and methodical application of prehabilitation exercise, ideally in the context of a comprehensive approach to lung cancer patients, including nutritional and psychological support.


Assuntos
Neoplasias Pulmonares/cirurgia , Pneumonectomia , Complicações Pós-Operatórias/epidemiologia , Cuidados Pré-Operatórios/métodos , Exercício Pré-Operatório , Exercícios Respiratórios/métodos , Treino Aeróbico/métodos , Treinamento Intervalado de Alta Intensidade/métodos , Humanos , Tempo de Internação/estatística & dados numéricos , Seleção de Pacientes
10.
Future Sci OA ; 7(2): FSO659, 2020 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-33437520

RESUMO

Pancreatic cancer remains an aggressive disease, with a poor prognosis and a high risk of incurring into cachexia. Supportive care, such as exercise, nutritional and psychological support, may be effective in reducing functional loss, psychological distress and improving nutritional status. We report the effect of 12 weeks of multimodal lifestyle intervention in a 55-year-old female, diagnosed with unresectable body/tail pancreatic cancer and metastasis in the liver, bone, lymph node and lung, to counteract cachexia. The multimodal program resulted safe and feasible. Over 12 weeks, considerable improvements were found in body weight, health-related physical fitness, nutritional status, distress scores, anxiety and depression levels. These findings highlight the potential role of integrated supportive interventions to manage metastatic cancer and cancer-induced cachexia.

11.
Sci Rep ; 9(1): 952, 2019 01 30.
Artigo em Inglês | MEDLINE | ID: mdl-30700813

RESUMO

The pre-conditioning of adult marine invertebrates to altered conditions, such as low pH, can significantly impact offspring outcomes, a process which is often referred to as transgenerational plasticity (TGP). This study describes for the first time, the gene expression profiles associated with TGP in the green sea urchin Psammechinus miliaris and evaluates the transcriptional contribution to larval resilience. RNA-Seq was used to determine how the expression profiles of larvae spawned into low pH from pre-acclimated adults differed to those of larvae produced from adults cultured under ambient pH. The main findings demonstrated that adult conditioning to low pH critically pre-loads the embryonic transcriptional pool with antioxidants to prepare the larvae for the "new" conditions. In addition, the classic cellular stress response, measured via the production of heat shock proteins (the heat shock response (HSR)), was separately evaluated. None of the early stage larvae either spawned in low pH (produced from both ambient and pre-acclimated adults) or subjected to a separate heat shock experiment were able to activate the full HSR as measured in adults, but the capacity to mount an HSR increased as development proceeded. This compromised ability clearly contributes to the vulnerability of early stage larvae to acute environmental challenge.


Assuntos
Adaptação Fisiológica/genética , Ouriços-do-Mar/genética , Animais , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Redes Reguladoras de Genes , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Resposta ao Choque Térmico/genética , Concentração de Íons de Hidrogênio , Larva/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Água do Mar , Transcriptoma/genética
12.
Oxid Med Cell Longev ; 2018: 9086947, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29849923

RESUMO

Mitochondria are fundamental organelles producing energy and reactive oxygen species (ROS); their impaired functions play a key role in endothelial dysfunction. Hydroxytyrosol (HT), a well-known olive oil antioxidant, exerts health benefits against vascular diseases by improving endothelial function. However, the HT role in mitochondrial oxidative stress in endothelial dysfunction is not clear yet. To investigate the HT effects on mitochondrial ROS production in the inflamed endothelium, we used an in vitro model of endothelial dysfunction represented by cultured endothelial cells, challenged with phorbol myristate acetate (PMA), an inflammatory, prooxidant, and proangiogenic agent. We found that the pretreatment of endothelial cells with HT (1-30 µmol/L) suppressed inflammatory angiogenesis, a crucial aspect of endothelial dysfunction. The HT inhibitory effect is related to reduced mitochondrial superoxide production and lipid peroxidation and to increased superoxide dismutase activity. HT, in a concentration-dependent manner, improved endothelial mitochondrial function by reverting the PMA-induced reduction of mitochondrial membrane potential, ATP synthesis, and ATP5ß expression. In PMA-challenged endothelial cells, HT also promoted mitochondrial biogenesis through increased mitochondrial DNA content and expression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha, nuclear respiratory factor-1, and mitochondrial transcription factor A. These results highlight that HT blunts endothelial dysfunction and pathological angiogenesis by ameliorating mitochondrial function, thus suggesting HT as a potential mitochondria-targeting antioxidant in the inflamed endothelium.


Assuntos
Mitocôndrias/efeitos dos fármacos , Álcool Feniletílico/análogos & derivados , Linhagem Celular , Movimento Celular/efeitos dos fármacos , DNA Mitocondrial/metabolismo , Células Endoteliais/citologia , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Células Endoteliais da Veia Umbilical Humana , Humanos , Malondialdeído/metabolismo , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/metabolismo , Neovascularização Fisiológica/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Álcool Feniletílico/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/metabolismo , Superóxidos/metabolismo , Acetato de Tetradecanoilforbol/farmacologia , Molécula 1 de Adesão de Célula Vascular/metabolismo
13.
J Hazard Mater ; 276: 469-79, 2014 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-24929786

RESUMO

For the first time, the zeta (ξ) potential of pathogenic mineral fibres (chrysotiles, amphiboles and erionite) was systematically investigated to shed light on the relationship between surface reactivity and fibre pathogenicity. A general model explaining the zeta potential of chrysotile, amphiboles and erionite has been postulated. In double distilled water, chrysotiles showed positive values while crocidolite and erionite showed negative values. In contact with organic solutions, all fibres exhibited negative values of zeta potential. The decrease of the surface potential is deemed to be a defensive chemical response of the macrophage cells to minimize hemolytic damage. Negatively charged surfaces favour the binding of collagen and redox activated Fe-rich proteins, to form the so-called asbestos bodies and prompt the formation of HO via the reaction with peroxide (H2O2+e(-)→HO+HO(-)). An additional mechanism accounting for higher carcinogenicity is possibly related to the Ca(2+) sequestration by the fibres with surface negative potential, impairing the mitochondrial apoptotic pathway. It was also found that with a negative zeta potential, the attractive forces prevailed over repulsions and favoured processes such as agglomeration responsible of a tumorigenic chronic inflammation.


Assuntos
Silicatos de Magnésio/química , Microscopia Eletrônica de Varredura
14.
Environ Sci Process Impacts ; 15(7): 1341-50, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23770928

RESUMO

The Valmalenco serpentinite (Central Alps, Northern Italy) is marketed worldwide as dimension and decorative stone. However, the same area was once subject to chrysotile asbestos mining, from the XIX century until 1975. Asbestos is a well-known carcinogen, and there is the possibility of releasing fibres during quarrying, subsequently exposing workers. From 2004 to 2011, extensive sampling and monitoring of quarry fronts, asbestos veins, commercial stones and airborne asbestos was carried out. Massive rock and vein samples were analyzed by a combined use of optical microscopy, X-ray powder diffraction (XRPD) and quantitative electron microscopy (SEM). Asbestos is concentrated almost exclusively in discrete horizons, that coincide with the main discontinuities of the rock mass. Commercial stones without fractures and veins are practically asbestos free, whereas there is a slight contamination (sometimes exceeding the 1000 ppm threshold) close to hydrothermal selvages. Quarry floors were always quite contaminated by chrysotile "beards" detached from the surface of the blocks. The airborne asbestos concentrations (PCM and SEM) were distributed over a wide range, mostly below the occupational exposure limit of 0.1 f ml(-1). Concentrations at the quarry property border or at the closest villages were always below the environmental exposure limit of 0.002 f ml(-1). The extreme thinness of chrysotile fibrils produced during quarrying activities, and the abundance of pseudo-fibrous antigorite cleavage fragments proved the SEM-EDS analytical procedure to be the most suitable. It is of crucial importance to avoid the interception of veins during quarrying and to remove all visible asbestos from the extracted blocks, before any further processing.


Assuntos
Poluentes Atmosféricos/análise , Asbestos Serpentinas/análise , Monitoramento Ambiental , Itália , Microscopia Eletrônica de Varredura , Mineração
15.
PLoS One ; 8(1): e52328, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23308110

RESUMO

Growing evidence shows that, among triiodothyronine derivatives, 3,5 diiodo-L-thyronine (T(2)) plays an important role in energy metabolism and fat storage. In the present study, short-term effects of T(2) administration to hypothyroid rats on fatty acid oxidation rate and bioenergetic parameters were investigated. Within 1 h following T(2) injection, state 3 and state 4 respiration rates, which were reduced in hypothyroid mitochondria, were noticeably increased particularly in succinate- with respect to glutamate/malate-energized mitochondria. Maximal respiratory activity, observed when glutamate/malate/succinate were simultaneously present in the respiratory medium, was significantly stimulated by T(2) treatment. A T(2)-induced increase in respiratory rates was also observed when palmitoyl-CoA or L-palmitoylcarnitine were used as substrates. No significant change in respiratory control index and ADP/O ratio was observed. The activities of the mitochondrial respiratory chain complexes, especially Complex II, were increased in T(2)-treated rats. In the latter, Complex V activities, assayed in both ATP synthesis and hydrolysis direction, were enhanced. The rate of fatty acid oxidation, followed by conversion of [(14)C]palmitate to CO(2) and ketone bodies, was higher in hepatocytes isolated from T(2)-treated rats. This increase occurs in parallel with the raise in the activity of carnitine palmitoyltransferase-I, the rate limiting enzyme of fatty acid ß-oxidation, assayed in situ in digitonin-permeabilized hepatocytes. Overall, these results indicate that T(2) rapidly increases the ability of mitochondria to import and oxidize fatty acids. An emerging idea in the literature is the ability of T(2) to reduce adiposity and dyslipidemia and to prevent the development in liver steatosis. The results of the present study, showing a rapid T(2)-induced increase in the ability of mitochondria to import and oxidize fatty acids, may contribute to understand the biochemical mechanisms of T(2)-metabolic effects.


Assuntos
Di-Iodotironinas/uso terapêutico , Metabolismo Energético/efeitos dos fármacos , Ácidos Graxos/metabolismo , Hepatócitos/efeitos dos fármacos , Hipotireoidismo/tratamento farmacológico , Hipotireoidismo/metabolismo , Animais , Células Cultivadas , Di-Iodotironinas/farmacologia , Hepatócitos/metabolismo , Masculino , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Oxirredução/efeitos dos fármacos , Ratos , Ratos Wistar
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