Intracellular glucose and binding of hexokinase and phosphofructokinase to particulate fractions increase under hypoxia in heart of the amazonian armored catfish (Liposarcus pardalis)
Armored catfish (Liposarcus pardalis), indigenous to the Amazon basin, have hearts that are extremely tolerant of oxygen limitation. Here we test the hypothesis that resistance to hypoxia is associated with increases in binding of selected glycolytic enzymes to subcellular fractions. Preparations of...
| Autor principal: | Treberg, Jason R. |
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| Outros Autores: | MacCormack, Tyson James, Lewis, Johanne Mari, Almeida-Val, Vera Maria Fonseca, Val, Adalberto Luis, Driedzic, William Robert |
| Grau: | Artigo |
| Idioma: | English |
| Publicado em: |
Physiological and Biochemical Zoology
2020
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| Acesso em linha: |
https://repositorio.inpa.gov.br/handle/1/18635 |
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oai:repositorio:1-18635 |
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oai:repositorio:1-18635 Intracellular glucose and binding of hexokinase and phosphofructokinase to particulate fractions increase under hypoxia in heart of the amazonian armored catfish (Liposarcus pardalis) Treberg, Jason R. MacCormack, Tyson James Lewis, Johanne Mari Almeida-Val, Vera Maria Fonseca Val, Adalberto Luis Driedzic, William Robert 6 Phosphofructokinase Citrate Synthase Fructose-bisphosphate Aldolase Glucose Hexokinase Lactate Dehydrogenase Lactic Acid Pyruvate Kinase 6 Phosphofructokinase Cardiovascular System Comparative Study Enzyme Activity Glucose Hypoxia Metabolism Muscle Particulate Matter Rodent Teleost Animals Catfish Cell Hypoxia Enzymology Glycolysis Heart Contraction Heart Mitochondrion Heart Muscle Heart Ventricle Heart Ventricle Function In Vitro Study Metabolism Physiology Animal Catfishes Cell Hypoxia Citrate (si)-synthase Fructose-bisphosphate Aldolase Glucose Glycolysis Heart Ventricles Hexokinase L-lactate Dehydrogenase Lactic Acid Mitochondria, Heart Myocardial Contraction Myocardium Phosphofructokinases Pyruvate Kinase Ventricular Function Amazon Basin South America Liposarcus Pardalis Mammalia Rattus Armored catfish (Liposarcus pardalis), indigenous to the Amazon basin, have hearts that are extremely tolerant of oxygen limitation. Here we test the hypothesis that resistance to hypoxia is associated with increases in binding of selected glycolytic enzymes to subcellular fractions. Preparations of isolated ventricular sheets were subjected to 2 h of either oxygenated or hypoxic (via nitrogen gassing) treatment during which time the muscle was stimulated to contract. The bathing medium contained 5 mM glucose and was maintained at 25°C. Initial experiments revealed increases in anaerobic metabolism, There was no measurable decrease in glycogen level; however, hypoxic treatment led to a twofold increase in heart glucose and a 10-fold increase in lactate content. It is suggested that the increase in heart glucose content is a result of an enhanced rate of facilitated glucose transport that exceeds the rate of phosphorylation of glucose. Further experiments assessed activities of metabolic enzymes in crude homogenates and subsequently tracked the degree of enzyme binding associated with subcellular fractions. Total maximal activities of glycolytic enzymes (hexokinase [HK], phosphofructokinase [PFK], aldolase, pyruvate kinase, lactate dehydrogenase), and a mitochondrial marker, citrate synthase, were not altered with the hypoxic treatment. A substantial portion (≥50%) of HK is permanently bound to mitochondria, and this level increases under hypoxia. The amount of HK that is bound to the mitochondrial fraction is at least fourfold higher in hearts of L. pardalis than in rat hearts. Hypoxia also resulted in increased binding of PFK to a particulate fraction, and the degree of binding is higher in hypoxia-tolerant fish than in hypoxia-sensitive mammalian hearts. Such binding may be associated with increased glycolytic flux rates through modulation of enzyme-specific kinetics. The binding of HK and PFK occurs before any significant decrease in glycogen level. © 2007 by The University of Chicago. All rights reserved. 2020-06-15T22:02:22Z 2020-06-15T22:02:22Z 2007 Artigo https://repositorio.inpa.gov.br/handle/1/18635 10.1086/520129 en Volume 80, Número 5, Pags. 542-550 Restrito Physiological and Biochemical Zoology |
| institution |
Instituto Nacional de Pesquisas da Amazônia - Repositório Institucional |
| collection |
INPA-RI |
| language |
English |
| topic |
6 Phosphofructokinase Citrate Synthase Fructose-bisphosphate Aldolase Glucose Hexokinase Lactate Dehydrogenase Lactic Acid Pyruvate Kinase 6 Phosphofructokinase Cardiovascular System Comparative Study Enzyme Activity Glucose Hypoxia Metabolism Muscle Particulate Matter Rodent Teleost Animals Catfish Cell Hypoxia Enzymology Glycolysis Heart Contraction Heart Mitochondrion Heart Muscle Heart Ventricle Heart Ventricle Function In Vitro Study Metabolism Physiology Animal Catfishes Cell Hypoxia Citrate (si)-synthase Fructose-bisphosphate Aldolase Glucose Glycolysis Heart Ventricles Hexokinase L-lactate Dehydrogenase Lactic Acid Mitochondria, Heart Myocardial Contraction Myocardium Phosphofructokinases Pyruvate Kinase Ventricular Function Amazon Basin South America Liposarcus Pardalis Mammalia Rattus |
| spellingShingle |
6 Phosphofructokinase Citrate Synthase Fructose-bisphosphate Aldolase Glucose Hexokinase Lactate Dehydrogenase Lactic Acid Pyruvate Kinase 6 Phosphofructokinase Cardiovascular System Comparative Study Enzyme Activity Glucose Hypoxia Metabolism Muscle Particulate Matter Rodent Teleost Animals Catfish Cell Hypoxia Enzymology Glycolysis Heart Contraction Heart Mitochondrion Heart Muscle Heart Ventricle Heart Ventricle Function In Vitro Study Metabolism Physiology Animal Catfishes Cell Hypoxia Citrate (si)-synthase Fructose-bisphosphate Aldolase Glucose Glycolysis Heart Ventricles Hexokinase L-lactate Dehydrogenase Lactic Acid Mitochondria, Heart Myocardial Contraction Myocardium Phosphofructokinases Pyruvate Kinase Ventricular Function Amazon Basin South America Liposarcus Pardalis Mammalia Rattus Treberg, Jason R. Intracellular glucose and binding of hexokinase and phosphofructokinase to particulate fractions increase under hypoxia in heart of the amazonian armored catfish (Liposarcus pardalis) |
| topic_facet |
6 Phosphofructokinase Citrate Synthase Fructose-bisphosphate Aldolase Glucose Hexokinase Lactate Dehydrogenase Lactic Acid Pyruvate Kinase 6 Phosphofructokinase Cardiovascular System Comparative Study Enzyme Activity Glucose Hypoxia Metabolism Muscle Particulate Matter Rodent Teleost Animals Catfish Cell Hypoxia Enzymology Glycolysis Heart Contraction Heart Mitochondrion Heart Muscle Heart Ventricle Heart Ventricle Function In Vitro Study Metabolism Physiology Animal Catfishes Cell Hypoxia Citrate (si)-synthase Fructose-bisphosphate Aldolase Glucose Glycolysis Heart Ventricles Hexokinase L-lactate Dehydrogenase Lactic Acid Mitochondria, Heart Myocardial Contraction Myocardium Phosphofructokinases Pyruvate Kinase Ventricular Function Amazon Basin South America Liposarcus Pardalis Mammalia Rattus |
| description |
Armored catfish (Liposarcus pardalis), indigenous to the Amazon basin, have hearts that are extremely tolerant of oxygen limitation. Here we test the hypothesis that resistance to hypoxia is associated with increases in binding of selected glycolytic enzymes to subcellular fractions. Preparations of isolated ventricular sheets were subjected to 2 h of either oxygenated or hypoxic (via nitrogen gassing) treatment during which time the muscle was stimulated to contract. The bathing medium contained 5 mM glucose and was maintained at 25°C. Initial experiments revealed increases in anaerobic metabolism, There was no measurable decrease in glycogen level; however, hypoxic treatment led to a twofold increase in heart glucose and a 10-fold increase in lactate content. It is suggested that the increase in heart glucose content is a result of an enhanced rate of facilitated glucose transport that exceeds the rate of phosphorylation of glucose. Further experiments assessed activities of metabolic enzymes in crude homogenates and subsequently tracked the degree of enzyme binding associated with subcellular fractions. Total maximal activities of glycolytic enzymes (hexokinase [HK], phosphofructokinase [PFK], aldolase, pyruvate kinase, lactate dehydrogenase), and a mitochondrial marker, citrate synthase, were not altered with the hypoxic treatment. A substantial portion (≥50%) of HK is permanently bound to mitochondria, and this level increases under hypoxia. The amount of HK that is bound to the mitochondrial fraction is at least fourfold higher in hearts of L. pardalis than in rat hearts. Hypoxia also resulted in increased binding of PFK to a particulate fraction, and the degree of binding is higher in hypoxia-tolerant fish than in hypoxia-sensitive mammalian hearts. Such binding may be associated with increased glycolytic flux rates through modulation of enzyme-specific kinetics. The binding of HK and PFK occurs before any significant decrease in glycogen level. © 2007 by The University of Chicago. All rights reserved. |
| format |
Artigo |
| author |
Treberg, Jason R. |
| author2 |
MacCormack, Tyson James Lewis, Johanne Mari Almeida-Val, Vera Maria Fonseca Val, Adalberto Luis Driedzic, William Robert |
| author2Str |
MacCormack, Tyson James Lewis, Johanne Mari Almeida-Val, Vera Maria Fonseca Val, Adalberto Luis Driedzic, William Robert |
| title |
Intracellular glucose and binding of hexokinase and phosphofructokinase to particulate fractions increase under hypoxia in heart of the amazonian armored catfish (Liposarcus pardalis) |
| title_short |
Intracellular glucose and binding of hexokinase and phosphofructokinase to particulate fractions increase under hypoxia in heart of the amazonian armored catfish (Liposarcus pardalis) |
| title_full |
Intracellular glucose and binding of hexokinase and phosphofructokinase to particulate fractions increase under hypoxia in heart of the amazonian armored catfish (Liposarcus pardalis) |
| title_fullStr |
Intracellular glucose and binding of hexokinase and phosphofructokinase to particulate fractions increase under hypoxia in heart of the amazonian armored catfish (Liposarcus pardalis) |
| title_full_unstemmed |
Intracellular glucose and binding of hexokinase and phosphofructokinase to particulate fractions increase under hypoxia in heart of the amazonian armored catfish (Liposarcus pardalis) |
| title_sort |
intracellular glucose and binding of hexokinase and phosphofructokinase to particulate fractions increase under hypoxia in heart of the amazonian armored catfish (liposarcus pardalis) |
| publisher |
Physiological and Biochemical Zoology |
| publishDate |
2020 |
| url |
https://repositorio.inpa.gov.br/handle/1/18635 |
| _version_ |
1787143563457331200 |
| score |
11.675608 |