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Jiang Q, Ji P, Ao S, Gao X, Zhang X. Effects of Starvation and Refeeding on Glucose Metabolism and Immune Responses in Macrobrachium rosenbergii. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2023:10.1007/s10126-023-10218-3. [PMID: 37249812 DOI: 10.1007/s10126-023-10218-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 05/19/2023] [Indexed: 05/31/2023]
Abstract
Starvation is a common challenge for aquatic animals in both natural and cultured environments. To investigate the effects of starvation and refeeding on glucose metabolism and immunity in Macrobrachium rosenbergii, prawns were starved for 14 days and then refed for 7 days. Results showed that both glucose and trehalose levels decreased significantly at the beginning of starvation, followed by a significant decrease in glycogen content in the hepatopancreas and muscle. Triglyceride and total protein reserves were also mobilized under starvation, with a slightly quicker response from triglycerides. The mRNA levels of glycolysis (glucokinase) and anabolism-related enzymes (glycogen branching enzyme, diacylglycerol acyltransferase, and transpeptidase) decreased during starvation, while gluconeogenic potential was induced, as indicated by up-regulated transcriptional levels of gluconeogenic enzymes (phosphoenolpyruvate carboxykinase) and catabolism-related enzymes (glycogen debranching enzyme, adipose triglyceride lipase, and cathepsin B). Starvation also stimulated the expression of the crustacean hyperglycemic hormone and inhibited insulin-like peptide expression, indicating their potential role in glucose metabolism regulation. In addition, starvation increased the mRNA levels of superoxide dismutase and prophenoloxidase, indicating an influence on the immune system. After bacterial infection, starved prawns showed enhanced activity of non-specific immunological parameters and reduced mortality. Refeeding for 7 days led to a recovery of physiological and biochemical indices and transcriptional levels of metabolism/immune-related genes. Our findings provide a better understanding of the mechanisms underlying energy utilization, metabolic adaptation, and immune response to starvation in M. rosenbergii.
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Affiliation(s)
- Qun Jiang
- College of Animal Science and Technology, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Peng Ji
- College of Animal Science and Technology, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Shiqi Ao
- College of Animal Science and Technology, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Xiaojian Gao
- College of Animal Science and Technology, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Xiaojun Zhang
- College of Animal Science and Technology, Yangzhou University, Yangzhou, 225009, Jiangsu, China.
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Dai Y, Shen Y, Guo J, Yang H, Chen F, Zhang W, Wu W, Xu X, Li J. Glycolysis and gluconeogenesis are involved of glucose metabolism adaptation during fasting and re-feeding in black carp (Mylopharyngodon piceus). AQUACULTURE AND FISHERIES 2022. [DOI: 10.1016/j.aaf.2022.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Marandel L, Plagnes-Juan E, Marchand M, Callet T, Dias K, Terrier F, Père S, Vernier L, Panserat S, Rétaux S. Nutritional regulation of glucose metabolism-related genes in the emerging teleost model Mexican tetra surface fish: a first exploration. ROYAL SOCIETY OPEN SCIENCE 2020; 7:191853. [PMID: 32257342 PMCID: PMC7062055 DOI: 10.1098/rsos.191853] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 01/30/2020] [Indexed: 06/11/2023]
Abstract
Astyanax mexicanus has gained importance as a laboratory model organism for evolutionary biology. However, little is known about its intermediary metabolism, and feeding regimes remain variable between laboratories holding this species. We thus aimed to evaluate the intermediary metabolism response to nutritional status and to low (NC) or high (HC) carbohydrate diets in various organs of the surface-dwelling form of the species. As expected, glycaemia increased after feeding. Fish fed the HC diet had higher glycaemia than fish fed the NC diet, but without displaying hyperglycaemia, suggesting that carbohydrates are efficiently used as an energy source. At molecular level, only fasn (Fatty Acid Synthase) transcripts increased in tissues after refeeding, suggesting an activation of lipogenesis. On the other hand, we monitored only moderate changes in glucose-related transcripts. Most changes observed were related to the nutritional status, but not to the NC versus HC diet. Such a metabolic pattern is suggestive of an omnivorous-related metabolism, and this species, at least at adult stage, may adapt to a fish meal-substituted diet with high carbohydrate content and low protein supply. Investigation to identify molecular actors explaining the efficient use of such a diet should be pursued to deepen our knowledge on this species.
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Affiliation(s)
- Lucie Marandel
- INRAE, Université de Pau & Pays de l'Adour, E2S UPPA, UMR1419 Nutrition Metabolism and Aquaculture, Aquapôle, 64310 Saint-Pée-sur-Nivelle, France
| | - Elisabeth Plagnes-Juan
- INRAE, Université de Pau & Pays de l'Adour, E2S UPPA, UMR1419 Nutrition Metabolism and Aquaculture, Aquapôle, 64310 Saint-Pée-sur-Nivelle, France
| | - Michael Marchand
- INRAE, Université de Pau & Pays de l'Adour, E2S UPPA, UMR1419 Nutrition Metabolism and Aquaculture, Aquapôle, 64310 Saint-Pée-sur-Nivelle, France
| | - Therese Callet
- INRAE, Université de Pau & Pays de l'Adour, E2S UPPA, UMR1419 Nutrition Metabolism and Aquaculture, Aquapôle, 64310 Saint-Pée-sur-Nivelle, France
| | - Karine Dias
- INRAE, Université de Pau & Pays de l'Adour, E2S UPPA, UMR1419 Nutrition Metabolism and Aquaculture, Aquapôle, 64310 Saint-Pée-sur-Nivelle, France
| | - Frederic Terrier
- INRAE, Université de Pau & Pays de l'Adour, E2S UPPA, UMR1419 Nutrition Metabolism and Aquaculture, Aquapôle, 64310 Saint-Pée-sur-Nivelle, France
| | - Stéphane Père
- Paris-Saclay Institute of Neuroscience, CNRS UMR9197, Université Paris-Saclay, Avenue de la terrasse, Gif-sur-Yvette, France
| | - Louise Vernier
- Paris-Saclay Institute of Neuroscience, CNRS UMR9197, Université Paris-Saclay, Avenue de la terrasse, Gif-sur-Yvette, France
| | - Stephane Panserat
- INRAE, Université de Pau & Pays de l'Adour, E2S UPPA, UMR1419 Nutrition Metabolism and Aquaculture, Aquapôle, 64310 Saint-Pée-sur-Nivelle, France
| | - Sylvie Rétaux
- Paris-Saclay Institute of Neuroscience, CNRS UMR9197, Université Paris-Saclay, Avenue de la terrasse, Gif-sur-Yvette, France
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Xu W, Li H, Wu L, Dong B, Jin J, Han D, Zhu X, Yang Y, Liu H, Xie S. Genetically Based Physiological Responses to Overwinter Starvation in Gibel Carp ( Carassius gibelio). Front Endocrinol (Lausanne) 2020; 11:578777. [PMID: 33329387 PMCID: PMC7711150 DOI: 10.3389/fendo.2020.578777] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 10/22/2020] [Indexed: 01/15/2023] Open
Abstract
Normally, fish will decrease food intake or even stop feeding during the winter. In previous studies, two widely cultured gibel carp strains (strain A and strain F) showed differences in lipid and glucose metabolism. Therefore, we hypothesized that the physiological changes during the overwintering period would be different between the two strains. Thus, the two strains were starved for 77 days, after which the levels of glucose and lipid metabolism, ER stress, autophagy, and apoptosis were determined. The starvation increased hepatic glycogenolysis and fatty acid β-oxidation but suppressed lipogenesis in both strains overwintering. Considering the effects of genotype, strain F had higher levels of ER stress and autophagy but lower levels of apoptosis than strain A, suggesting that strain F might be more resistant to overwintering starvation. The interactions between strains and starvation periods were observed in plasma triglyceride contents and the mRNA levels of pyruvate kinase (pk), sterol regulatory element binding protein 1 (srebp1), activating transcription factor 4 (atf4), and autophagy protein 12 (atg12). In conclusion, long-term starvation during winter could induce hepatic glycogenolysis and fatty acid β-oxidation but suppress lipogenesis, ER stress, autophagy, and apoptosis in gibel carp, and strain F may be more resistant to starvation during winter. Taken together, these results discovered the responses to prolonged starvation stress during winter in two strains of gibel carp and could provide information for genotype selection, especially for selecting strains better adapted to winter.
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Affiliation(s)
- Wenjie Xu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Hongyan Li
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Liyun Wu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Bo Dong
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Junyan Jin
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- *Correspondence: Junyan Jin,
| | - Dong Han
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Xiaoming Zhu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Yunxia Yang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Haokun Liu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Shouqi Xie
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
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Li X, Wang T, Yin S, Zhang G, Cao Q, Wen X, Zhang H, Wang D, Zhu W. The improved energy metabolism and blood oxygen-carrying capacity for pufferfish, Takifugu fasciatus, against acute hypoxia under the regulation of oxygen sensors. FISH PHYSIOLOGY AND BIOCHEMISTRY 2019; 45:323-340. [PMID: 30225749 DOI: 10.1007/s10695-018-0565-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Accepted: 08/28/2018] [Indexed: 06/08/2023]
Abstract
Hypoxia frequently occurs in aquatic ecosystem, which is influenced by salinity, water temperature, weather, and surface water runoff. In order to shed further light on the evolutionary and adaptive mechanisms in fish under hypoxic condition, the impact of acute hypoxia (1.63 ± 0.2 mg/L) and reoxygenation (7.0 ± 0.3 mg/L) on oxygen sensors, energy metabolism, and hematological indices was evaluated in Takifugu fasciatus. Data from transcriptional level analysis show that the expressions of genes related to oxygen sensors (HIF-1α, PHD2, and VHL) were upregulated in the brain and liver under hypoxia and recovered under reoxygenation. The upregulation of GLUT2, VEGF-A, and EPO in conjugation with VEGF-A protein and hematological indices conferred the rapid adjustments of cellular glucose uptake and blood oxygen-carrying capacities in pufferfish. Higher levels of glycolysis-related mRNAs (HK, PGK1, and PGAM2), HK activity, and proteins (PGK1 and PGAM2) were detected in the brain and liver under hypoxic condition compared with control. Interestingly, the expression of MDH1 at the mRNA, enzyme activity, and protein levels was significantly increased in the brain at 0 or 2 h and in the liver at 8 h under hypoxic condition. In addition, although the enzyme activity and mRNA expression of LDH in the brain were not significantly changed, a persistent upregulation was observed in the liver during hypoxia exposure. This study demonstrated that pufferfish could counterpoise the energetic demands and hematological functional properties evoked by oxygen sensors after hypoxia. Our findings provided new insights into the molecular regulatory mechanism of hypoxia in pufferfish.
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Affiliation(s)
- Xinru Li
- College of Marine Science and Engineering, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, Jiangsu, China
- Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, 222005, Jiangsu, China
| | - Tao Wang
- College of Marine Science and Engineering, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, Jiangsu, China.
- Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, 222005, Jiangsu, China.
| | - Shaowu Yin
- College of Marine Science and Engineering, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, Jiangsu, China.
- Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, 222005, Jiangsu, China.
| | - Guosong Zhang
- College of Marine Science and Engineering, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, Jiangsu, China
- Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, 222005, Jiangsu, China
| | - Quanquan Cao
- College of Marine Science and Engineering, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, Jiangsu, China
- Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, 222005, Jiangsu, China
| | - Xin Wen
- College of Marine Science and Engineering, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, Jiangsu, China
- Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, 222005, Jiangsu, China
| | - Hongye Zhang
- College of Marine Science and Engineering, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, Jiangsu, China
- Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, 222005, Jiangsu, China
| | - Dan Wang
- College of Marine Science and Engineering, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, Jiangsu, China
- Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, 222005, Jiangsu, China
| | - Wenxu Zhu
- College of Marine Science and Engineering, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, Jiangsu, China
- Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, 222005, Jiangsu, China
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Gaspar C, Silva-Marrero JI, Salgado MC, Baanante IV, Metón I. Role of upstream stimulatory factor 2 in glutamate dehydrogenase gene transcription. J Mol Endocrinol 2018; 60:247-259. [PMID: 29438976 DOI: 10.1530/jme-17-0142] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 02/08/2018] [Indexed: 12/18/2022]
Abstract
Glutamate dehydrogenase (Gdh) plays a central role in ammonia detoxification by catalysing reversible oxidative deamination of l-glutamate into α-ketoglutarate using NAD+ or NADP+ as cofactor. To gain insight into transcriptional regulation of glud, the gene that codes for Gdh, we isolated and characterised the 5' flanking region of glud from gilthead sea bream (Sparus aurata). In addition, tissue distribution, the effect of starvation as well as short- and long-term refeeding on Gdh mRNA levels in the liver of S. aurata were also addressed. 5'-Deletion analysis of glud promoter in transiently transfected HepG2 cells, electrophoretic mobility shift assays, chromatin immunoprecipitation (ChIP) and site-directed mutagenesis allowed us to identify upstream stimulatory factor 2 (Usf2) as a novel factor involved in the transcriptional regulation of glud Analysis of tissue distribution of Gdh and Usf2 mRNA levels by reverse transcriptase-coupled quantitative real-time PCR (RT-qPCR) showed that Gdh is mainly expressed in the liver of S. aurata, while Usf2 displayed ubiquitous distribution. RT-qPCR and ChIP assays revealed that long-term starvation down-regulated the hepatic expression of Gdh and Usf2 to similar levels and reduced Usf2 binding to glud promoter, while refeeding resulted in a slow but gradual restoration of both Gdh and Usf2 mRNA abundance. Herein, we demonstrate that Usf2 transactivates S. aurata glud by binding to an E-box located in the proximal region of glud promoter. In addition, our findings provide evidence for a new regulatory mechanism involving Usf2 as a key factor in the nutritional regulation of glud transcription in the fish liver.
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Affiliation(s)
- Carlos Gaspar
- Secció de Bioquímica i Biologia Molecular, Departament de Bioquímica i Fisiologia, Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona, Barcelona, Spain
| | - Jonás I Silva-Marrero
- Secció de Bioquímica i Biologia Molecular, Departament de Bioquímica i Fisiologia, Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona, Barcelona, Spain
| | - María C Salgado
- Servei de Bioquímica Clínica, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Isabel V Baanante
- Secció de Bioquímica i Biologia Molecular, Departament de Bioquímica i Fisiologia, Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona, Barcelona, Spain
| | - Isidoro Metón
- Secció de Bioquímica i Biologia Molecular, Departament de Bioquímica i Fisiologia, Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona, Barcelona, Spain
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Rito J, Viegas I, Pardal MA, Metón I, Baanante IV, Jones JG. Disposition of a Glucose Load into Hepatic Glycogen by Direct and Indirect Pathways in Juvenile Seabass and Seabream. Sci Rep 2018; 8:464. [PMID: 29323287 PMCID: PMC5765127 DOI: 10.1038/s41598-017-19087-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 12/19/2017] [Indexed: 02/06/2023] Open
Abstract
In carnivorous fish, conversion of a glucose load to hepatic glycogen is widely used to assess their metabolic flexibility towards carbohydrate utilization, but the activities of direct and indirect pathways in this setting are unclear. We assessed the conversion of an intraperitoneal glucose load (2 g.kg-1) enriched with [U-13C6]glucose to hepatic glycogen in juvenile seabass and seabream. 13C-NMR analysis of glycogen was used to determine the contribution of the load to glycogen synthesis via direct and indirect pathways at 48-hr post-injection. For seabass, [U-13C6]glucose was accompanied by deuterated water and 2H-NMR analysis of glycogen 2H-enrichment, allowing endogenous substrate contributions to be assessed as well. For fasted seabass and seabream, 47 ± 5% and 64 ± 10% of glycogen was synthesized from the load, respectively. Direct and indirect pathways contributed equally (25 ± 3% direct, 21 ± 1% indirect for seabass; 35 ± 7% direct, 29 ± 4% indirect for seabream). In fasted seabass, integration of 2H- and 13C-NMR analysis indicated that endogenous glycerol and anaplerotic substrates contributed an additional 7 ± 2% and 7 ± 1%, respectively. In fed seabass, glucose load contributions were residual and endogenous contributions were negligible. Concluding, direct and indirect pathways contributed equally and substantially to fasting hepatic glycogen repletion from a glucose load in juvenile seabream and seabass.
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Affiliation(s)
- João Rito
- CNC - Center for Neuroscience and Cell Biology, Rua Larga, 1° Piso da FMUC, University of Coimbra, 3004-504, Coimbra, Portugal
- CFE - Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Ivan Viegas
- CNC - Center for Neuroscience and Cell Biology, Rua Larga, 1° Piso da FMUC, University of Coimbra, 3004-504, Coimbra, Portugal
- CFE - Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Miguel A Pardal
- CFE - Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Isidoro Metón
- Secció de Bioquímica i Biologia Molecular, Departament de Bioquímica i Fisiologia, Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona (UB), Joan XXIII 27, 08028, Barcelona, Spain
| | - Isabel V Baanante
- Secció de Bioquímica i Biologia Molecular, Departament de Bioquímica i Fisiologia, Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona (UB), Joan XXIII 27, 08028, Barcelona, Spain
| | - John G Jones
- CNC - Center for Neuroscience and Cell Biology, Rua Larga, 1° Piso da FMUC, University of Coimbra, 3004-504, Coimbra, Portugal.
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Liang X, Wang J, Gong G, Xue M, Dong Y, Wu X, Wang X, Chen C, Liang X, Qin Y. Gluconeogenesis during starvation and refeeding phase is affected by previous dietary carbohydrates levels and a glucose stimuli during early life in Siberian sturgeon ( Acipenser baerii). ACTA ACUST UNITED AC 2017; 3:284-294. [PMID: 29767079 PMCID: PMC5941230 DOI: 10.1016/j.aninu.2017.06.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 05/31/2017] [Accepted: 06/02/2017] [Indexed: 12/17/2022]
Abstract
Gluconeogenesis responses was assessed during a short starvation period and subsequent refeeding in Siberian sturgeon (Acipenser baerii) previously fed different dietary carbohydrates levels and experienced to a glucose stimuli during early life. The sturgeon larvae were previously fed either a high glucose diet (G) or a low glucose diet (F) from the first feeding to yolk absorption (8 to 12 d post-hatching [dph]). Each group of fish was sub-divided into 2 treatments at 13 dph and was fed either a high-carbohydrate diet (H) or a low carbohydrate diet (L) until 20 wk. In the current study, the fish in 4 groups (GL, FL, GH and FH) were experienced to starvation for 21 d following by re-feeding of their corresponding diets for 21 d. Fish were sampled at postprandial 6 and 24 h before starvation (P6h and P24h), starvation 7, 14 and 21 d (S7, S14 and S21) and 1, 7, 14 and 21 d during refeeding (R1, R7, R14 and R21). Plasma samples during refeeding were taken at P6h at each time point. Glycaemia levels, liver and muscle glycogen contents, activities and mRNA levels of hepatic gluconeogenic enzymes were examined. We found that both dietary carbohydrate levels and early glucose stimuli significantly affected the metabolic responses to starvation and refeeding in Siberian sturgeon (P < 0.05). During prolonged starvation, Siberian sturgeon firstly mobilized the liver glycogen and then improved gluconeogenesis when the dietary carbohydrates were abundant, whereas preserved the liver glycogen stores at a stable level and more effectively promoted gluconeogenesis when the dietary carbohydrates are absent to maintain glucose homoeostasis. During refeeding, as most teleostean, Siberian sturgeon failed controlling the activities and mRNA levels of phosphoenolpyruvate carboxykinase cytosolic forms (PEPCK-C), fructose-1,6-bisphosphatase (FBPase), but particularly controlled phosphoenolpyruvate carboxykinase mitochondrial forms (PEPCK-M) activities and mRNA expression of glucose-6-phosphatase (G6Pase, except in GL group). Siberian sturgeon has a full compensatory ability on growth, but this ability would be obstructed by early glucose stimuli when refeeding the low carbohydrate diet after S21.
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Affiliation(s)
- Xiaofang Liang
- National Aquafeed Safety Assessment Station, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Jia Wang
- National Aquafeed Safety Assessment Station, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China.,Key Laboratory of Feed Biotechnology of Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Guan Gong
- National Aquafeed Safety Assessment Station, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Min Xue
- National Aquafeed Safety Assessment Station, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China.,Key Laboratory of Feed Biotechnology of Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Yingchao Dong
- National Aquafeed Safety Assessment Station, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Xiufeng Wu
- National Aquafeed Safety Assessment Station, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Xin Wang
- National Aquafeed Safety Assessment Station, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Chunshan Chen
- Beijing Aquatic Wildlife Rescue and Conservation Center, Beijing 102100, China
| | - Xufang Liang
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China
| | - Yuchang Qin
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China
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Chen YJ, Zhang TY, Chen HY, Lin SM, Luo L, Wang DS. Simultaneous stimulation of glycolysis and gluconeogenesis by feeding in the anterior intestine of the omnivorous GIFT tilapia, Oreochromis niloticus. Biol Open 2017; 6:818-824. [PMID: 28619994 PMCID: PMC5483027 DOI: 10.1242/bio.024836] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The present study was performed to investigate the roles of anterior intestine in the postprandial glucose homeostasis of the omnivorous Genetically Improved Farmed Tilapia (GIFT). Sub-adult fish (about 173 g) were sampled at 0, 1, 3, 8 and 24 h post feeding (HPF) after 36 h of food deprivation, and the time course of changes in intestinal glucose transport, glycolysis, glycogenesis and gluconeogenesis at the transcription and enzyme activity level, as well as plasma glucose contents, were analyzed. Compared with 0 HPF (fasting for 36 h), the mRNA levels of both ATP-dependent sodium/glucose cotransporter 1 and facilitated glucose transporter 2 increased during 1-3 HPF, decreased at 8 HPF and then leveled off. These results indicated that intestinal uptake of glucose and its transport across the intestine to blood mainly occurred during 1-3 HPF, which subsequently resulted in the increase of plasma glucose level at the same time. Intestinal glycolysis was stimulated during 1-3 HPF, while glucose storage as glycogen was induced during 3-8 HPF. Unexpectedly, intestinal gluconeogenesis (IGNG) was also strongly induced during 1-3 HPF at the state of nutrient assimilation. The mRNA abundance and enzyme activities of glutamic-pyruvic and glutamic-oxaloacetic transaminases increased during 1-3 HPF, suggesting that the precursors of IGNG might originate from some amino acids. Taken together, it was concluded that the anterior intestine played an important role in the regulation of postprandial glucose homeostasis in omnivorous tilapia, as it represented significant glycolytic potential and glucose storage. It was interesting that postprandial IGNG was stimulated by feeding temporarily, and its biological significance remains to be elucidated in fish.
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Affiliation(s)
- Yong-Jun Chen
- Key Laboratory of Freshwater Fish Resources and Reproductive Development (Ministry of Education), College of Animal Science and Technology, Southwest University, Chongqing 400715, China .,Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Ti-Yin Zhang
- Key Laboratory of Freshwater Fish Resources and Reproductive Development (Ministry of Education), College of Animal Science and Technology, Southwest University, Chongqing 400715, China
| | - Hai-Yan Chen
- Key Laboratory of Freshwater Fish Resources and Reproductive Development (Ministry of Education), College of Animal Science and Technology, Southwest University, Chongqing 400715, China
| | - Shi-Mei Lin
- Key Laboratory of Freshwater Fish Resources and Reproductive Development (Ministry of Education), College of Animal Science and Technology, Southwest University, Chongqing 400715, China
| | - Li Luo
- Key Laboratory of Freshwater Fish Resources and Reproductive Development (Ministry of Education), College of Animal Science and Technology, Southwest University, Chongqing 400715, China
| | - De-Shou Wang
- Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing 400715, China
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Conde-Sieira M, Soengas JL. Nutrient Sensing Systems in Fish: Impact on Food Intake Regulation and Energy Homeostasis. Front Neurosci 2017; 10:603. [PMID: 28111540 PMCID: PMC5216673 DOI: 10.3389/fnins.2016.00603] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 12/19/2016] [Indexed: 12/27/2022] Open
Abstract
Evidence obtained in recent years in a few species, especially rainbow trout, supports the presence in fish of nutrient sensing mechanisms. Glucosensing capacity is present in central (hypothalamus and hindbrain) and peripheral [liver, Brockmann bodies (BB, main accumulation of pancreatic endocrine cells in several fish species), and intestine] locations whereas fatty acid sensors seem to be present in hypothalamus, liver and BB. Glucose and fatty acid sensing capacities relate to food intake regulation and metabolism in fish. Hypothalamus is as a signaling integratory center in a way that detection of increased levels of nutrients result in food intake inhibition through changes in the expression of anorexigenic and orexigenic neuropeptides. Moreover, central nutrient sensing modulates functions in the periphery since they elicit changes in hepatic metabolism as well as in hormone secretion to counter-regulate changes in nutrient levels detected in the CNS. At peripheral level, the direct nutrient detection in liver has a crucial role in homeostatic control of glucose and fatty acid whereas in BB and intestine nutrient sensing is probably involved in regulation of hormone secretion from endocrine cells.
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Affiliation(s)
- Marta Conde-Sieira
- Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía, Universidade de Vigo Vigo, Spain
| | - José L Soengas
- Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía, Universidade de Vigo Vigo, Spain
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11
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Glucosensing in liver and Brockmann bodies of rainbow trout through glucokinase-independent mechanisms. Comp Biochem Physiol B Biochem Mol Biol 2016; 199:29-42. [DOI: 10.1016/j.cbpb.2015.09.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 09/17/2015] [Accepted: 09/25/2015] [Indexed: 01/21/2023]
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12
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Polakof S, Panserat S. How Tom Moon's research highlighted the question of glucose tolerance in carnivorous fish. Comp Biochem Physiol B Biochem Mol Biol 2016; 199:43-49. [DOI: 10.1016/j.cbpb.2015.11.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 10/30/2015] [Accepted: 11/01/2015] [Indexed: 11/15/2022]
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13
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Véron V, Panserat S, Le Boucher R, Labbé L, Quillet E, Dupont-Nivet M, Médale F. Long-term feeding a plant-based diet devoid of marine ingredients strongly affects certain key metabolic enzymes in the rainbow trout liver. FISH PHYSIOLOGY AND BIOCHEMISTRY 2016; 42:771-785. [PMID: 26746847 DOI: 10.1007/s10695-015-0174-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 11/24/2015] [Indexed: 06/05/2023]
Abstract
Incorporation of a plant blend in the diet can affect growth parameters and metabolism in carnivorous fish. We studied for the first time the long-term (1 year) metabolic response of rainbow trout fed from first feeding with a plant-based diet totally devoid of marine ingredients. Hepatic enzymes were analyzed at enzymatic and molecular levels, at 3, 8 and 24 h after the last meal to study both the short-term effects of the last meal and long-term effects of the diet. The results were compared with those of fish fed a control diet of fish meal and fish oil. Growth, feed intake, feed efficiency and protein retention were lower in the group fed the plant-based diet. Glucokinase and pyruvate kinase activity were lower in the livers of trout fed the plant-based diet which the proportion of starch was lower than in the control diet. Glutamate dehydrogenase was induced by the plant-based diet, suggesting an imbalance of amino acids and a possible link with the lower protein retention observed. Gene expression of delta 6 desaturase was higher in fish fed the plant-based diet, probably linked to a high dietary level of linolenic acid and the absence of long-chain polyunsaturated fatty acids in vegetable oils. Hydroxymethylglutaryl-CoA synthase expression was also induced by plant-based diet because of the low rate of cholesterol in the diet. Changes in regulation mechanisms already identified through short-term nutritional experiments (<12 weeks) suggest that metabolic responses are implemented at short term and remain in the long term.
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Affiliation(s)
- Vincent Véron
- INRA UR 1067 NuMeA (Nutrition Metabolism Aquaculture), Aquapôle, 64310, Saint Pée Sur Nivelle, France.
| | - Stéphane Panserat
- INRA UR 1067 NuMeA (Nutrition Metabolism Aquaculture), Aquapôle, 64310, Saint Pée Sur Nivelle, France
| | - Richard Le Boucher
- INRA, UMR1313 GABI (Génétique animale et biologie intégrative), Jouy-En-Josas, France
| | - Laurent Labbé
- INRA, UE 0937 PEIMA (Pisciculture Expérimentale INRA des Monts d'Arrée), Sizun, France
| | - Edwige Quillet
- INRA, UMR1313 GABI (Génétique animale et biologie intégrative), Jouy-En-Josas, France
| | - Mathilde Dupont-Nivet
- INRA, UMR1313 GABI (Génétique animale et biologie intégrative), Jouy-En-Josas, France
| | - Françoise Médale
- INRA UR 1067 NuMeA (Nutrition Metabolism Aquaculture), Aquapôle, 64310, Saint Pée Sur Nivelle, France
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14
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Hernández-Pérez J, Míguez JM, Librán-Pérez M, Otero-Rodiño C, Naderi F, Soengas JL, López-Patiño MA. Daily rhythms in activity and mRNA abundance of enzymes involved in glucose and lipid metabolism in liver of rainbow trout, Oncorhynchus mykiss. Influence of light and food availability. Chronobiol Int 2015; 32:1391-408. [PMID: 26587750 DOI: 10.3109/07420528.2015.1100633] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The present research aimed to investigate in a model of teleost fish (rainbow trout) the existence of daily changes in activity and mRNA abundance of several proteins involved in major pathways of carbohydrate and lipid metabolism in liver, and to test whether or not both the light-dark cycle and food availability might influence such rhythms. For this purpose, four cohorts of animals previously adapted to normal housing conditions (12L:12D; Lights on at ZT0; feeding time at ZT2) were subjected to: normal conditions (LD); 48-h constant darkness (DD); 96-h food deprivation (LD + Fasting); or constant darkness and food deprivation (DD + Fasting) respectively. After such time periods, fish were sacrificed and sampled every 4-h on the following 24-h period (ZT/CT0, 4, 8, 12, 16, 20 and 0'). Our results reveal that cortisol and all the analysed genes (gk, pepck, g6pase, pk, glut2, hoad and fas) exhibited well defined daily rhythms, which persisted even in the absence of light and/or food indicating the endogenous nature of such rhythms. Even when the variations of enzyme activities were not significant, their rhythms mostly paralleled those of the respective gene expression. The rhythms of mRNA abundance were apparently dependent on the presence of food, but the light/dark cycle also influenced such rhythms. Since cortisol does not appear to be mainly involved in generating such daily rhythms in liver, alternative mechanisms might be involved, such as a direct interaction between metabolism and the circadian system.
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Affiliation(s)
- Juan Hernández-Pérez
- a Laboratorio de Fisioloxía Animal , Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía, Universidade de Vigo , Vigo (Pontevedra) , Spain
| | - Jesús M Míguez
- a Laboratorio de Fisioloxía Animal , Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía, Universidade de Vigo , Vigo (Pontevedra) , Spain
| | - Marta Librán-Pérez
- a Laboratorio de Fisioloxía Animal , Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía, Universidade de Vigo , Vigo (Pontevedra) , Spain
| | - Cristina Otero-Rodiño
- a Laboratorio de Fisioloxía Animal , Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía, Universidade de Vigo , Vigo (Pontevedra) , Spain
| | - Fatemeh Naderi
- a Laboratorio de Fisioloxía Animal , Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía, Universidade de Vigo , Vigo (Pontevedra) , Spain
| | - José L Soengas
- a Laboratorio de Fisioloxía Animal , Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía, Universidade de Vigo , Vigo (Pontevedra) , Spain
| | - Marcos A López-Patiño
- a Laboratorio de Fisioloxía Animal , Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía, Universidade de Vigo , Vigo (Pontevedra) , Spain
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15
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Tian J, He G, Mai K, Liu C. Effects of postprandial starvation on mRNA expression of endocrine-, amino acid and peptide transporter-, and metabolic enzyme-related genes in zebrafish (Danio rerio). FISH PHYSIOLOGY AND BIOCHEMISTRY 2015; 41:773-787. [PMID: 25805459 DOI: 10.1007/s10695-015-0045-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 03/18/2015] [Indexed: 06/04/2023]
Abstract
The goal of this study was to systematically evaluate the molecular activities of endocrine-, amino acid and peptide transporters-, and metabolic enzyme-related genes in 35-day-old mixed-sex zebrafish (Danio rerio) after feeding . Zebrafish with initial body weights ranging from 9 to 11 mg were fasted for 384 h in a controlled indoor environment. Fish were sampled at 0, 3, 6, 12, 24, 48, 96, 192, and 384 h after fed. Overall, the present study results show that the regulatory mechanism that insulin-like growth factor I negative feedback regulated growth hormone is conserved in zebrafish, as it is in mammals, but that regulation of growth hormone receptors is highly intricate. Leptin and cholecystokinin are time-dependent negative feedback signals, and neuropeptide Y may be an important positive neuropeptide for food intake in zebrafish. The amino acid/carnitine transporters B(0,+) (ATB(0,+)) and broad neutral (0) amino acid transporter 1(B(0)AT1) mRNA levels measured in our study suggest that protein may be utilized during 24-96 h of fasting in zebrafish. Glutamine synthetase mRNA levels were downregulated, and glutamate dehydrogenase, alanine aminotransferase, aspartate transaminase, and trypsin mRNA levels were upregulated after longtime fasting in this study. The mRNA expression levels of fatty acid synthetase decreased significantly (P < 0.05), whereas those of lipoprotein lipase rapidly increased after 96 h of fasting. Fasting activated the expression of glucose synthesis genes when fasting for short periods of time; when fasting is prolonged, the mRNA levels of glucose breakdown enzymes and pentose phosphate shunt genes decreased.
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Affiliation(s)
- Juan Tian
- Key Laboratory of Aquaculture Nutrition (Ministry of Agriculture), Ocean University of China, No. 5 Yushan Rd., Qingdao, 266003, People's Republic of China,
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16
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Blanco AM, Gómez-Boronat M, Pérez-Maceira J, Mancebo MJ, Aldegunde M. Brain glycogen supercompensation after different conditions of induced hypoglycemia and sustained swimming in rainbow trout (Oncorhynchus mykiss). Comp Biochem Physiol A Mol Integr Physiol 2015; 187:55-60. [PMID: 25956213 DOI: 10.1016/j.cbpa.2015.04.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 04/27/2015] [Accepted: 04/28/2015] [Indexed: 11/17/2022]
Abstract
Brain glycogen is depleted when used as an emergency energy substrate. In mammals, brain glycogen levels rebound to higher than normal levels after a hypoglycemic episode and a few hours after refeeding or administration of glucose. This phenomenon is called glycogen supercompensation. However, this mechanism has not been investigated in lower vertebrates. The aim of this study was therefore to determine whether brain glycogen supercompensation occurs in the rainbow trout brain. For this purpose, short-term brain glucose and glycogen contents were determined in rainbow trout after being subjected to the following experimental conditions: i) a 5-day or 10-day fasting period and refeeding; ii) a single injection of insulin (4 mg kg(-1)) and refeeding; and iii) sustained swimming and injection of glucose (500 mg kg(-1)). Food deprivation during the fasting periods and insulin administration both induced a decrease in glucose and glycogen levels in the brain. However, only refeeding after 10 days of fasting significantly increased the brain glycogen content above control levels, in a clear short-term supercompensation response. Unlike in mammals, prolonged exercise did not alter brain glucose or glycogen levels. Furthermore, brain glycogen supercompensation was not observed after glucose administration in fish undergoing sustained swimming. To our knowledge, this is the first study providing direct experimental evidence for the existence of a short-term glycogen supercompensation response in a teleost brain, although the response was only detectable after prolonged fasting.
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Affiliation(s)
- A M Blanco
- Laboratorio de Fisiología Animal (Instituto de Acuicultura), Facultad de Biología, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - M Gómez-Boronat
- Laboratorio de Fisiología Animal (Instituto de Acuicultura), Facultad de Biología, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - J Pérez-Maceira
- Laboratorio de Fisiología Animal (Instituto de Acuicultura), Facultad de Biología, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - M J Mancebo
- Laboratorio de Fisiología Animal (Instituto de Acuicultura), Facultad de Biología, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - M Aldegunde
- Laboratorio de Fisiología Animal (Instituto de Acuicultura), Facultad de Biología, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
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17
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Glucose metabolism and gene expression in juvenile zebrafish (Danio rerio) challenged with a high carbohydrate diet: effects of an acute glucose stimulus during late embryonic life. Br J Nutr 2015; 113:403-13. [PMID: 25609020 DOI: 10.1017/s0007114514003869] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Knowledge on the role of early nutritional stimuli as triggers of metabolic pathways in fish is extremely scarce. The objective of the present study was to assess the long-term effects of glucose injection in the yolk (early stimulus) on carbohydrate metabolism and gene regulation in zebrafish juveniles challenged with a high-carbohydrate low-protein (HC) diet. Eggs were microinjected at 1 d post-fertilisation (dpf) with either glucose (2 M) or saline solutions. Up to 25 dpf, fish were fed a low-carbohydrate high-protein (LC) control diet, which was followed by a challenge with the HC diet. Survival and growth of 35 dpf juveniles were not affected by injection or the HC diet. Glucose stimulus induced some long-term metabolic changes in the juveniles, as shown by the altered expression of genes involved in glucose metabolism. On glycolysis, the expression levels of hexokinase 1 (HK1) and phosphofructokinase-6 (6PFK) were up-regulated in the visceral and muscle tissues, respectively, of juveniles exposed to the glucose stimulus, indicating a possible improvement in glucose oxidation. On gluconeogenesis, the inhibition of the expression levels of PEPCK in fish injected with glucose suggested lower production of hepatic glucose. Unexpectedly, fructose-1,6-bisphosphatase (FBP) expression was induced and 6PFK expression reduced by glucose stimulus, leaving the possibility of a specific regulation of the FBP-6PFK metabolic cycle. Glucose metabolism in juveniles was estimated using a [¹⁴C]glucose tracer; fish previously exposed to the stimulus showed lower retention of [¹⁴C]glucose in visceral tissue (but not in muscle tissue) and, accordingly, higher glucose catabolism, in comparison with the saline group. Globally, our data suggest that glucose stimulus at embryo stage has the potential to alter particular steps of glucose metabolism in zebrafish juveniles.
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18
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Soengas JL. Contribution of glucose- and fatty acid sensing systems to the regulation of food intake in fish. A review. Gen Comp Endocrinol 2014; 205:36-48. [PMID: 24530522 DOI: 10.1016/j.ygcen.2014.01.015] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 01/13/2014] [Accepted: 01/28/2014] [Indexed: 01/01/2023]
Abstract
Food intake in fish is a complex process regulated through many different factors including abundance of energy and nutrients. In recent years, evidence have been obtained in several fishes, mainly in rainbow trout, regarding the presence and functioning in brain areas of metabolic sensors informing about changes in the levels of nutrients like glucose and fatty acids. The activity of these sensors relate to the control of food intake through changes in the expression of anorexigenic and orexigenic neuropeptides. The present review will provide a picture of the main results obtained to date in these studies, as well as perspectives for future research in the field.
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Affiliation(s)
- José L Soengas
- Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía, Universidade de Vigo, Spain.
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19
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Abstract
The glucokinase (GK) enzyme (EC 2.7.1.1.) is essential for the use of dietary glucose because it is the first enzyme to phosphorylate glucose in excess in different key tissues such as the pancreas and liver. The objective of the present review is not to fully describe the biochemical characteristics and the genetics of this enzyme but to detail its nutritional regulation in different vertebrates from fish to human. Indeed, the present review will describe the existence of the GK enzyme in different animal species that have naturally different levels of carbohydrate in their diets. Thus, some studies have been performed to analyse the nutritional regulation of the GK enzyme in humans and rodents (having high levels of dietary carbohydrates in their diets), in the chicken (moderate level of carbohydrates in its diet) and rainbow trout (no carbohydrate intake in its diet). All these data illustrate the nutritional importance of the GK enzyme irrespective of feeding habits, even in animals known to poorly use dietary carbohydrates (carnivorous species).
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Viegas I, Caballero-Solares A, Rito J, Giralt M, Pardal MA, Metón I, Jones JG, Baanante IV. Expressional regulation of key hepatic enzymes of intermediary metabolism in European seabass (Dicentrarchus labrax) during food deprivation and refeeding. Comp Biochem Physiol A Mol Integr Physiol 2014; 174:38-44. [PMID: 24746983 DOI: 10.1016/j.cbpa.2014.04.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 04/04/2014] [Accepted: 04/07/2014] [Indexed: 11/18/2022]
Abstract
We hypothesized that the analysis of mRNA level and activity of key enzymes in amino acid and carbohydrate metabolism in a feeding/fasting/refeeding setting could improve our understanding of how a carnivorous fish, like the European seabass (Dicentrarchus labrax), responds to changes in dietary intake at the hepatic level. To this end cDNA fragments encoding genes for cytosolic and mitochondrial alanine aminotransferase (cALT; mALT), pyruvate kinase (PK), glucose 6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) were cloned and sequenced. Measurement of mRNA levels through quantitative real-time PCR performed in livers of fasted seabass revealed a significant increase in cALT (8.5-fold induction) while promoting a drastic 45-fold down-regulation of PK in relation to the levels found in fed seabass. These observations were corroborated by enzyme activity meaning that during food deprivation an increase in the capacity of pyruvate generation happened via alanine to offset the reduction in pyruvate derived via glycolysis. After a 3-day refeeding period cALT returned to control levels while PK was not able to rebound. No alterations were detected in the expression levels of G6PDH while 6PGDH was revealed to be more sensitive specially to fasting, as confirmed by a significant 5.7-fold decrease in mRNA levels with no recovery after refeeding. Our results indicate that in early stages of refeeding, the liver prioritized the restoration of systemic normoglycemia and replenishment of hepatic glycogen. In a later stage, once regular feeding is re-established, dietary fuel may then be channeled to glycolysis and de novo lipogenesis.
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Affiliation(s)
- Ivan Viegas
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; CFE - Center for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martins de Freitas 3000-456 Coimbra, Portugal.
| | - Albert Caballero-Solares
- Departament d'Ecologia, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 645, 08028 Barcelona, Spain
| | - João Rito
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal; CFE - Center for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martins de Freitas 3000-456 Coimbra, Portugal
| | - Marina Giralt
- Departament de Bioquímica i Biologia Molecular, Facultat de Farmàcia, Universitat de Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain
| | - Miguel A Pardal
- CFE - Center for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martins de Freitas 3000-456 Coimbra, Portugal
| | - Isidoro Metón
- Departament de Bioquímica i Biologia Molecular, Facultat de Farmàcia, Universitat de Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain
| | - John G Jones
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal
| | - Isabel V Baanante
- Departament de Bioquímica i Biologia Molecular, Facultat de Farmàcia, Universitat de Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain
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Mennigen JA, Martyniuk CJ, Seiliez I, Panserat S, Skiba-Cassy S. Metabolic consequences of microRNA-122 inhibition in rainbow trout, Oncorhynchus mykiss. BMC Genomics 2014; 15:70. [PMID: 24467738 PMCID: PMC3914182 DOI: 10.1186/1471-2164-15-70] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2013] [Accepted: 01/22/2014] [Indexed: 01/31/2023] Open
Abstract
Background MicroRNAs (miRNAs) are small regulatory molecules which post-transcriptionally regulate mRNA stability and translation. Several microRNAs have received attention due to their role as key metabolic regulators. In spite of the high evolutionary conservation of several miRNAs, the role of miRNAs in lower taxa of vertebrates has not been studied with regard to metabolism. The liver-specific and highly abundant miRNA-122 is one of the most widely studied miRNA in mammals, where it has been implicated in the control of hepatic lipid metabolism. Following our identification of acute postprandial, nutritional and endocrine regulation of hepatic miRNA-122 isomiRNA expression in rainbow trout, we used complementary in silico and in vivo approaches to study the role of miRNA-122 in rainbow trout metabolism. We hypothesized that the role of miRNA-122 in regulating lipid metabolism in rainbow trout is conserved to that in mammals and that modulation of miRNA-122 function would result in altered lipid homeostasis and secondarily altered glucose homeostasis, since lipogenesis has been suggested to act as glucose sink in trout. Results Our results show that miRNA-122 was functionally inhibited in vivo in the liver. Postprandial glucose concentrations increased significantly in rainbow trout injected with a miRNA-122 inhibitor, and this effect correlated with decreases in hepatic FAS protein abundance, indicative of altered lipogenic potential. Additionally, miRNA-122 inhibition resulted in a 20% decrease in plasma cholesterol concentration, an effect associated with increased expression of genes involved in cholesterol degradation and excretion. Conclusions Overall evidence suggests that miRNA-122 may have evolved in early vertebrates to support liver-specific metabolic functions. Nevertheless, our data also indicate that metabolic consequences of miRNA-122 inhibition may differ quantitatively between vertebrate species and that distinct direct molecular targets of miRNA-122 may mediate metabolic effects between vertebrate species, indicating that miRNA-122 - mRNA target relationships may have undergone species-specific evolutionary changes.
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Affiliation(s)
| | | | | | | | - Sandrine Skiba-Cassy
- Institut National de la Recherche Agronomique (INRA), Nutrition, Metabolism and Aquaculture Unit (UR1067), Saint-Pée-sur-Nivelle F-64310, France.
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Schermerhorn T. Normal glucose metabolism in carnivores overlaps with diabetes pathology in non-carnivores. Front Endocrinol (Lausanne) 2013; 4:188. [PMID: 24348462 PMCID: PMC3847661 DOI: 10.3389/fendo.2013.00188] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 11/19/2013] [Indexed: 12/15/2022] Open
Abstract
Carnivores, such as the dolphin and the domestic cat, have numerous adaptations that befit consumption of diets with high protein and fat content, with little carbohydrate content. Consequently, nutrient metabolism in carnivorous species differs substantially from that of non-carnivores. Important metabolic pathways known to differ between carnivores and non-carnivores are implicated in the development of diabetes and insulin resistance in non-carnivores: (1) the hepatic glucokinase (GCK) pathway is absent in healthy carnivores yet GCK deficiency may result in diabetes in rodents and humans, (2) healthy dolphins and cats are prone to periods of fasting hyperglycemia and exhibit insulin resistance, both of which are risk factors for diabetes in non-carnivores. Similarly, carnivores develop naturally occurring diseases such as hemochromatosis, fatty liver, obesity, and diabetes that have strong parallels with the same disorders in humans. Understanding how evolution, environment, diet, and domestication may play a role with nutrient metabolism in the dolphin and cat may also be relevant to human diabetes.
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Affiliation(s)
- Thomas Schermerhorn
- Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA
- *Correspondence: Thomas Schermerhorn, Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, 1800 Denison Avenue, Manhattan, KS 66506-5606, USA e-mail:
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23
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Viegas I, Rito J, González JD, Jarak I, Carvalho RA, Metón I, Pardal MA, Baanante IV, Jones JG. Effects of food-deprivation and refeeding on the regulation and sources of blood glucose appearance in European seabass (Dicentrarchus labrax L.). Comp Biochem Physiol A Mol Integr Physiol 2013; 166:399-405. [PMID: 23871878 DOI: 10.1016/j.cbpa.2013.07.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 07/09/2013] [Accepted: 07/10/2013] [Indexed: 02/06/2023]
Abstract
Sources of blood glucose in European seabass (initial weight 218.0±43.0g; mean±S.D., n=18) were quantified by supplementing seawater with deuterated water (5%-(2)H2O) for 72h and analyzing blood glucose (2)H-enrichments by (2)H NMR. Three different nutritional states were studied: continuously fed, 21-day of fast and 21-day fast followed by 3days of refeeding. Plasma glucose levels (mM) were 10.7±6.3 (fed), 4.8±1.2 (fasted), and 9.3±1.4 (refed) (means±S.D., n=6), showing poor glycemic control. For all conditions, (2)H-enrichment of glucose position 5 was equivalent to that of position 2 indicating that blood glucose appearance from endogenous glucose 6-phosphate (G6P) was derived by gluconeogenesis. G6P-derived glucose accounted for 65±7% and 44±10% of blood glucose appearance in fed and refed fish, respectively, with the unlabeled fraction assumed to be derived from dietary carbohydrate (35±7% and 56±10%, respectively). For 21-day fasted fish, blood glucose appearance also had significant contributions from unlabeled glucose (52±16%) despite the unavailability of dietary carbohydrates. To assess the role of hepatic enzymes in glycemic control, activity and mRNA levels of hepatic glucokinase (GK) and glucose 6-phosphatase (G6Pase) were assessed. Both G6Pase activity and expression declined with fasting indicating the absence of a classical counter-regulatory stimulation of hepatic glucose production in response to declining glucose levels. GK activities were basal during fed and fasted conditions, but were strongly stimulated by refeeding. Overall, hepatic G6Pase and GK showed limited capacity in regulating glucose levels between feeding and fasting states.
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Affiliation(s)
- Ivan Viegas
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal; CFE-Center for Functional Ecology, University of Coimbra, Apartado 3046, 3001-401 Coimbra, Portugal; Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, 3001-401 Coimbra, Portugal.
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24
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Evidence of sugar sensitive genes in the gut of a carnivorous fish species. Comp Biochem Physiol B Biochem Mol Biol 2013; 166:58-64. [PMID: 23850750 DOI: 10.1016/j.cbpb.2013.07.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 07/01/2013] [Accepted: 07/04/2013] [Indexed: 12/17/2022]
Abstract
The ability of intestine to sense glucose in carnivorous animals (consuming minimal carbohydrate) has been partially evaluated to date only in cats. We have evaluated the expression of markers involved in the detection of simple sugars in the intestine of the strict carnivorous fish species rainbow trout (Oncorhynchus mykiss) in response to an oral glucose load and to glucose, galactose and mannose stimulation in vitro. These markers include metabolic (GLUT2 and glucokinase (hexokinase IV, GK)) and electrogenic (SGLT1) sensors, the nuclear receptor nr1h3 and the components of the G-protein-coupled taste receptors (tas1r2-like, tas1r3-like and gnat3-like). For the first time, we show that the gut of rainbow trout can detect simple sugars including glucose, galactose and mannose and respond by changing the expression levels of glucose-sensing proteins. The glucosensing response based on the metabolic and nuclear receptor systems had not been evidenced before in any carnivorous vertebrate species, whereas the responses of markers of the electrogenic mechanism and the taste receptor mechanism were different than those already described in cats. When the responses observed in rainbow trout were compared with those of omnivorous mammals, similar responses were obtained for nr1h3 whereas several differences arise in the responses of the other markers. Intestinal glucose sensing in the rainbow trout appears to be distinct from that reported for other carnivores such as cats and omnivores, revealing a novel glucose sensing mechanism not related entirely to diet in vertebrates and supports the idea that this species constitute a robust model for nutrient sensing study. Since only mRNA abundance is presented, depth studies are needed to fully understand the importance of the present findings.
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25
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Feed restriction and genetic selection on the expression and activity of metabolism regulatory enzymes in rabbits. Animal 2012; 4:1873-83. [PMID: 22445148 DOI: 10.1017/s1751731110001047] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
This work aims at the identification of relevant intermediate metabolism enzymes contributing to improved meat production due to genetic selection. A wild rabbit (WR) breed and a highly meat selected breed (New Zealand (NZ) rabbit) were used. Food restriction was used as an experimental condition so as to enhance differences within the metabolic pathways under study. During a period of 30 days, NZ and WR experimental breeds were subjected to, respectively, 40% and 60% ad libitum food restriction leading to 17.7% and 21.1% initial weight. Hepatic glycolytic, lipidic and protein regulatory enzyme activity, transcriptional and metabolite levels were determined. Insulin-like growth factor (IGF-1), triiodothyronine, and cortisol were also evaluated. In the glycolytic pathways, the NZ control rabbits presented a higher phosphofructokinase and pyruvate kinase activity level when compared to the WR, while the latter group showed a higher expression of glycogen synthase, although with less glycogen content. In the nitrogen metabolism, our results showed a lower activity level of glutamate dehydrogenase in WR when subjected to food restriction. Within the lipid metabolism, results showed that although WR had a significantly higher mRNA hepatic lipase, non-esterified fatty acid levels were similar between the experimental groups. NZ rabbits presented a better glycemia control and greater energy substrate availability leading to enhanced productivities in which triiodothyronine and IGF-1 played a relevant role.
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26
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Niu J, Lin HZ, Jiang SG, Chen X, Wu KC, Tian LX, Liu YJ. Effect of seven carbohydrate sources on juvenile Penaeus monodon growth performance, nutrient utilization efficiency and hepatopancreas enzyme activities of 6-phosphogluconate dehydrogenase, hexokinase and amylase. Anim Feed Sci Technol 2012. [DOI: 10.1016/j.anifeedsci.2012.03.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Conde-Sieira M, Patiño MAL, Míguez JM, Soengas JL. Glucosensing capacity in rainbow trout liver displays day-night variations possibly related to melatonin action. ACTA ACUST UNITED AC 2012; 215:3112-9. [PMID: 22660781 DOI: 10.1242/jeb.069740] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
To assess whether the glucosensing capacity in peripheral (liver and Brockmann bodies) and central (hypothalamus and hindbrain) locations of rainbow trout displays day-night variations in its response to changes in circulating glucose levels, we evaluated the response of parameters related to glucosensing [glucose, glycogen and glucose 6-phosphate levels, activities of glucokinase (GK), glycogen synthetase (GSase) and pyruvate kinase (PK), and mRNA abundance of GK, glucose transporter 2 (GLUT2), and K(ATP) channel subunits Kir6.x-like and sulfonylurea receptor (SUR)-like] in fish subjected to hyperglycemic treatment under night or day conditions. No day-night significant variations were noticed in the glucosensing capacity of the hypothalamus, hindbrain and Brockmann bodies. In contrast, a clear differential response was noticed in the liver, where glucose levels, GK activity (and mRNA levels) and GSase activity displayed increased values during the day in hyperglycemic fish compared with controls, and lower (GK mRNA levels) or non-existent (glucose, GK and GSase activities, and Kir6.x-like mRNA levels) values during the night. A similar decrease in parameters related to glucosensing in the liver was observed when fish under day conditions were treated with melatonin, suggesting a modulatory role of melatonin in day-night changes of the glucosensing response in the same tissue.
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Affiliation(s)
- Marta Conde-Sieira
- Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía, Universidade de Vigo, E-36310 Vigo, Spain
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28
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Glucose metabolism in fish: a review. J Comp Physiol B 2012; 182:1015-45. [PMID: 22476584 DOI: 10.1007/s00360-012-0658-7] [Citation(s) in RCA: 376] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 03/06/2012] [Accepted: 03/10/2012] [Indexed: 02/07/2023]
Abstract
Teleost fishes represent a highly diverse group consisting of more than 20,000 species living across all aquatic environments. This group has significant economical, societal and environmental impacts, yet research efforts have concentrated primarily on salmonid and cyprinid species. This review examines carbohydrate/glucose metabolism and its regulation in these model species including the role of hormones and diet. Over the past decade, molecular tools have been used to address some of the downstream components of these processes and these are incorporated to better understand the roles played by carbohydrates and their regulatory paths. Glucose metabolism remains a contentious area as many fish species are traditionally considered glucose intolerant and, therefore, one might expect that the use and storage of glucose would be considered of minor importance. However, the actual picture is not so clear since the apparent intolerance of fish to carbohydrates is not evident in herbivorous and omnivorous species and even in carnivorous species, glucose is important for specific tissues and/or for specific activities. Thus, our aim is to up-date carbohydrate metabolism in fish, placing it to the context of these new experimental tools and its relationship to dietary intake. Finally, we suggest that new research directions ultimately will lead to a better understanding of these processes.
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Glucose and lipid metabolism in the pancreas of rainbow trout is regulated at the molecular level by nutritional status and carbohydrate intake. J Comp Physiol B 2011; 182:507-16. [PMID: 22203338 DOI: 10.1007/s00360-011-0636-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2011] [Revised: 12/08/2011] [Accepted: 12/09/2011] [Indexed: 10/14/2022]
Abstract
Glucose and lipid metabolism in pancreatic islet organs is poorly characterized. In the present study, using as a model the carnivorous rainbow trout, a glucose-intolerant fish, we assessed mRNA expression levels of several genes involved in glucose and lipid metabolism (including ATP-citrate lyase; carnitine palmitoyltransferase-1 isoforms, CPT; the mitochondrial isoform of the phosphoenolpyrutave carboxykinase, mPEPCK and pyruvate kinase, PK) and glucosensing (glucose transporter type 2, Glut2; glucokinase, GK and the potassium channel, K(ATP)) in Brockmann bodies. We evaluated the response of these parameters to changes in feeding status (food deprived vs. fed fish) as well as to changes in the amount of carbohydrate (dextrin) in the diet. A general inhibition of the glycolytic (including the glucosensing marker GK) and β-oxidation pathways was found when comparing fed versus food-deprived fish. When comparing fish feeding on either low- or high-carbohydrate diets, we found that some genes related to lipid metabolism were more controlled by the feeding status than by the carbohydrate content (fatty acid synthase, CPTs). Findings are discussed in the context of pancreatic regulation of glucose and lipid metabolism in fish, and show that while trout pancreatic metabolism can partially adapt to a high-carbohydrate diet, some of the molecular actors studied seem to be poorly regulated (K(ATP)) and may contribute to the glucose intolerance observed in this species when fed high-carbohydrate diets.
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Polakof S, Míguez JM, Soengas JL. Cholecystokinin impact on rainbow trout glucose homeostasis: Possible involvement of central glucosensors. ACTA ACUST UNITED AC 2011; 172:23-9. [DOI: 10.1016/j.regpep.2011.08.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 07/15/2011] [Accepted: 08/12/2011] [Indexed: 12/15/2022]
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Polakof S, Mommsen TP, Soengas JL. Glucosensing and glucose homeostasis: from fish to mammals. Comp Biochem Physiol B Biochem Mol Biol 2011; 160:123-49. [PMID: 21871969 DOI: 10.1016/j.cbpb.2011.07.006] [Citation(s) in RCA: 205] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Revised: 07/20/2011] [Accepted: 07/22/2011] [Indexed: 12/16/2022]
Abstract
This review is focused on two topics related to glucose in vertebrates. In a first section devoted to glucose homeostasis we describe how glucose levels fluctuate and are regulated in different classes of vertebrates. The detection of these fluctuations is essential for homeostasis and for other physiological processes such as regulation of food intake. The capacity of that detection is known as glucosensing, and the different mechanisms through which it occurs are known as glucosensors. Different glucosensor mechanisms have been demonstrated in different tissues and organs of rodents and humans whereas the information obtained for other vertebrates is scarce. In the second section of the review we describe the present knowledge regarding glucosensor mechanisms in different groups of vertebrates, with special emphasis in fish.
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Affiliation(s)
- Sergio Polakof
- INRA, UMR, UNH, CRNH Auvergne, Clermont-Ferrand, France.
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32
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Polakof S, Míguez JM, Soengas JL. Evidence for a gut-brain axis used by glucagon-like peptide-1 to elicit hyperglycaemia in fish. J Neuroendocrinol 2011; 23:508-18. [PMID: 21564347 DOI: 10.1111/j.1365-2826.2011.02137.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
In mammals, glucagon-like peptide-1 (GLP-1) produces changes in glucose and energy homeostasis through a gut-pancreas-brain axis. In fish, the effects of GLP-1 are opposed to those described in other vertebrates, such as stimulation of hyperglycaemia and the lack of an effect of incretin. In the present study conducted in a teleost fish such as the rainbow trout, we present evidence of a gut-brain axis used by GLP-1 to exert its actions on glucose and energy homeostasis. We have assessed the effects of GLP-1 on glucose metabolism in the liver as well as the glucose-sensing potential in the hypothalamus and hindbrain. We confirm that peripheral GLP-1 administration elicits sustained hyperglycaemia, whereas, for the first time in a vertebrate species, we report that central GLP-1 treatment increases plasma glucose levels. We have observed (using capsaicin) that at least part of the action of GLP-1 on glucose homeostasis was mediated by vagal and splanchnic afferents. GLP-1 has a direct effect in parameters involved in glucose sensing in the hindbrain, whereas, in the hypothalamus, changes occurred indirectly through hyperglycaemia. Moreover, in the hindbrain, GLP-1 altered the expression of peptides involved in the control of food intake. We have elaborated a model for the actions of GLP-1 in fish in which this peptide uses a mammalian-like ancestral gut-brain axis to elicit the regulation of glucose homeostasis in different manner than the model described in mammals. Finally, it is worth noting that the hyperglycaemia induced by this peptide and the lack of incretin function could be related to the glucose intolerance observed in carnivorous teleost fish species such as the rainbow trout.
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Affiliation(s)
- S Polakof
- Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía, Universidade de Vigo, Vigo, Spain.
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Aguilar AJ, Conde-Sieira M, López-Patiño MA, Míguez JM, Soengas JL. In vitro leptin treatment of rainbow trout hypothalamus and hindbrain affects glucosensing and gene expression of neuropeptides involved in food intake regulation. Peptides 2011; 32:232-40. [PMID: 21093510 DOI: 10.1016/j.peptides.2010.11.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Revised: 11/08/2010] [Accepted: 11/08/2010] [Indexed: 11/20/2022]
Abstract
The aim of the present study was to evaluate in hypothalamus and hindbrain of rainbow trout in vitro the effect of leptin treatment on glucosensing capacity and the expression of orexigenic and anorexigenic peptides involved in the control of food intake. In a first experiment, the response of parameters involved in glucosensing (GK, PK and GSase activities; GK expression and glucose; glycogen and DHAP levels) and the expression of orexigenic (NPY) and anorexigenic (POMC, CART, CRF) peptides was assessed in hypothalami and hindbrain incubated for 1h with 2, 4 or 8mM d-glucose alone (controls) or with 10nM leptin, or with 10nM leptin plus inhibitors of leptin signaling pathways (50nM wortmannin and 500nM AG490). Leptin treatment increased levels in parameters involved in glucosensing. Leptin treatment decreased NPY mRNA levels in hypothalamus without affecting the expression of the other peptides assessed. Leptin effects were reverted in the presence of inhibitors for all parameters assessed suggesting the involvement of JAK/STAT and IRS-PI(3)K pathways. In a second experiment, we observed time-dependent (1-3h) and dose (10, 20 and 50nM)- effects of leptin treatment in decreasing NPY mRNA levels without affecting expression of the other peptides assessed. Considering the orexigenic action of NPY in fish, it seems that the anorexic effect of leptin can be mediated by reduced expression of NPY occurring in hypothalamus, and that change can be related to the activation of the glucosensing system occurring simultaneously.
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Affiliation(s)
- Ariel J Aguilar
- Departamento de Bioloxía Funcional e Ciencias da Saúde, Universidade de Vigo, Vigo, Spain
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Polakof S, Moon TW, Aguirre P, Skiba-Cassy S, Panserat S. Glucose homeostasis in rainbow trout fed a high-carbohydrate diet: metformin and insulin interact in a tissue-dependent manner. Am J Physiol Regul Integr Comp Physiol 2011; 300:R166-74. [DOI: 10.1152/ajpregu.00619.2010] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Carnivorous fish species such as the rainbow trout ( Oncorhynchus mykiss ) are considered to be “glucose intolerant” because of the prolonged hyperglycemia experienced after intake of a carbohydrate-enriched meal. In the present study, we use this species to study glucose homeostasis in fish chronically infused with the hypoglycemic agents, insulin, and metformin, and fed with a high proportion of carbohydrates (30%). We analyzed liver, skeletal muscle, and white adipose tissue (WAT), which are insulin- and metformin-specific targets at both the biochemical and molecular levels. Trout infused with the combination of insulin and metformin can effectively utilize dietary glucose at the liver, resulting in lowered glycemia, increased insulin sensitivity, and glucose storage capacity, combined with reduced glucose output. However, in both WAT and skeletal muscle, we observed decreased insulin sensitivity with the combined insulin + metformin treatment, resulting in the absence of changes at the metabolic level in the skeletal muscle and an increased potential for glucose uptake and storage in the WAT. Thus, the poor utilization by rainbow trout of a diet with a high proportion of carbohydrate can at least be partially improved by a combined treatment with insulin and metformin, and the glucose intolerance observed in this species could be, in part, due to some of the downstream components of the insulin and metformin signaling pathways. However, the predominant effects of metformin treatment on the action of insulin in these three tissues thought to be involved in glucose homeostasis remain exclusive in this species.
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Affiliation(s)
- S. Polakof
- Institut National de la Recherche Agronomique, UMR1067 Nutrition Aquaculture et Génomique, Saint-Pée-sur-Nivelle, France
- Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía, Universidade de Vigo, Vigo, Spain; and
| | - T. W. Moon
- Department of Biology and Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Ontario, Canada
| | - P. Aguirre
- Institut National de la Recherche Agronomique, UMR1067 Nutrition Aquaculture et Génomique, Saint-Pée-sur-Nivelle, France
| | - S. Skiba-Cassy
- Institut National de la Recherche Agronomique, UMR1067 Nutrition Aquaculture et Génomique, Saint-Pée-sur-Nivelle, France
| | - S. Panserat
- Institut National de la Recherche Agronomique, UMR1067 Nutrition Aquaculture et Génomique, Saint-Pée-sur-Nivelle, France
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35
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Harmon KJ, Bolinger MT, Rodnick KJ. Carbohydrate energy reserves and effects of food deprivation in male and female rainbow trout. Comp Biochem Physiol A Mol Integr Physiol 2010; 158:423-31. [PMID: 21130180 DOI: 10.1016/j.cbpa.2010.11.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2010] [Revised: 11/22/2010] [Accepted: 11/24/2010] [Indexed: 11/18/2022]
Abstract
We investigated the effects of nutritional state on carbohydrate, lipid, and protein stores in the heart, liver, and white skeletal muscle of male and female rainbow trout. For fed animals we also partitioned glycogen into fractions based on acid solubility. Fish (10-14 months-old, ~400-500 g) were held at 14 °C and either fed (1% of body weight, every other day) or deprived of food for 14 days. Under fed conditions, glycogen was increased 54% in ventricles from males compared with females, and elevated in the liver (87%) and white muscle (70%) in sexually-maturing versus immature males. Acid soluble glycogen predominated over the acid insoluble fraction in all tissues and was similar between sexes. Food deprivation 1) selectively reduced glycogen and free glucose in male ventricles by ~30%, and 2) did not change glycogen in the liver or white muscle, or triglyceride, protein or water levels in any tissues for both sexes. These data highlight sex differences in teleost cardiac stores and the metabolism of carbohydrates, and contrast with mammals where cardiac glycogen increases during fasting and acid insoluble glycogen is a significant fraction. Increased glycogen in the hearts of male rainbow trout appears to pre-empt sex-specific cardiac growth while storage of acid soluble glycogen may reflect a novel strategy for efficient synthesis and mobilization of glycogen in fishes.
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Affiliation(s)
- Kelli J Harmon
- Department of Biological Sciences, Idaho State University, Pocatello, ID 83209-8007, USA
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Characterization of non-cytosolic hexokinase activity in white skeletal muscle from goldfish (Carassius auratus L.) and the effect of cold acclimation. Biosci Rep 2010; 30:413-23. [DOI: 10.1042/bsr20090128] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
HK (hexokinase) is an enzyme involved in the first step in the glucose metabolism pathway, converting glucose into G6P (glucose 6-phosphate). Owing to the importance of skeletal muscle for fish swimming and acclimation processes, we used goldfish (Carassius auratus L.) white muscle in order to investigate subcellular distribution and kinetics of HK. In this study, we report that HK activity is predominantly localized in the mitochondrial fraction [NC-HK (non-cytosolic HK)] in goldfish white muscle. Studies of the kinetic parameters revealed that the Km (Michaelis–Menten constant) for glucose was 0.41±0.03 mM and that for mannose was 3-fold lower, whereas the affinity for fructose was too low to be measured. The Km for ATP was 0.88±0.05 mM, whereas no activity was observed when either GTP or ITP was used as a phosphate donor. A moderate inhibition (20–40%) was found for ADP and AMP. Similar to mammalian HK, G6P and glucose analogues were able to promote an inhibition of between 85 and 100% of activity. Here, we found that acclimation of goldfish at 5°C promoted a 2.5-fold increase in NC-HK compared with its counterpart acclimated at 25°C. However, cytosolic HK activity was not altered after thermal acclimation. In summary, our results suggest that the goldfish has a constitutive NC-HK that shows some similarities to mammalian HK-II and, curiously, may play a role in the broad metabolic changes required during the cold acclimation process.
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Enes P, Panserat S, Kaushik S, Oliva-Teles A. Nutritional regulation of hepatic glucose metabolism in fish. FISH PHYSIOLOGY AND BIOCHEMISTRY 2009; 35:519-539. [PMID: 18791853 DOI: 10.1007/s10695-008-9259-5] [Citation(s) in RCA: 172] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2008] [Accepted: 07/27/2008] [Indexed: 05/26/2023]
Abstract
Glucose plays a key role as energy source in the majority of mammals, but its importance in fish appears limited. Until now, the physiological basis for such apparent glucose intolerance in fish has not been fully understood. A distinct regulation of hepatic glucose utilization (glycolysis) and production (gluconeogenesis) may be advanced to explain the relative inability of fish to efficiently utilize dietary glucose. We summarize here information regarding the nutritional regulation of key enzymes involved in glycolysis (hexokinases, 6-phosphofructo-1-kinase and pyruvate kinase) and gluconeogenesis (phosphoenolpyruvate carboxykinase, fructose-1,6-bisphosphatase and glucose-6-phosphatase) pathways as well as that of the bifunctional enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase. The effect of dietary carbohydrate level and source on the activities and gene expression of the mentioned key enzymes is also discussed. Overall, data strongly suggest that the liver of most fish species is apparently capable of regulating glucose storage. The persistent high level of endogenous glucose production independent of carbohydrate intake level may lead to a putative competition between exogenous (dietary) glucose and endogenous glucose as the source of energy, which may explain the poor dietary carbohydrate utilization in fish.
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Affiliation(s)
- P Enes
- Departamento de Zoologia e Antropologia, Faculdade de Ciências, Universidade do Porto, 4169-007, Porto, Portugal.
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Friedel CC, Dölken L, Ruzsics Z, Koszinowski UH, Zimmer R. Conserved principles of mammalian transcriptional regulation revealed by RNA half-life. Nucleic Acids Res 2009; 37:e115. [PMID: 19561200 PMCID: PMC2761256 DOI: 10.1093/nar/gkp542] [Citation(s) in RCA: 168] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
RNA levels in a cell are regulated by the relative rates of RNA synthesis and decay. We recently developed a new approach for measuring both RNA synthesis and decay in a single experimental setting by biosynthetic labeling of newly transcribed RNA. Here, we show that this provides measurements of RNA half-lives from microarray data with a so far unreached accuracy. Based on such measurements of RNA half-lives for human B-cells and mouse fibroblasts, we identified conserved regulatory principles for a large number of biological processes. We show that different regulatory patterns between functionally similar proteins are characterized by differences in the half-life of the corresponding transcripts and can be identified by measuring RNA half-life. We identify more than 100 protein families which show such differential regulatory patterns in both species. Additionally, we provide strong evidence that the activity of protein complexes consisting of subunits with overall long transcript half-lives can be regulated by transcriptional regulation of individual key subunits with short-lived transcripts. Based on this observation, we predict more than 100 key regulatory subunits for human complexes of which 28% could be confirmed in mice (P < 10−9). Therefore, this atlas of transcript half-lives provides new fundamental insights into many cellular processes.
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Affiliation(s)
- Caroline C. Friedel
- Institute for Informatics, Ludwig-Maximilians-Universität München, Munich 80333 and Max von Pettenkofer-Institute, Ludwig-Maximilians-Universität München, Munich 80337, Germany
- *To whom correspondence should be addressed. Tel: +49-89-2180-4056; Fax: +49-89-2180-4054; Correspondence may also be addressed to Dr Lars Dölken. Tel: +49-89-5160-5290; Fax: +49-89-5160-5292;
| | - Lars Dölken
- Institute for Informatics, Ludwig-Maximilians-Universität München, Munich 80333 and Max von Pettenkofer-Institute, Ludwig-Maximilians-Universität München, Munich 80337, Germany
- *To whom correspondence should be addressed. Tel: +49-89-2180-4056; Fax: +49-89-2180-4054; Correspondence may also be addressed to Dr Lars Dölken. Tel: +49-89-5160-5290; Fax: +49-89-5160-5292;
| | - Zsolt Ruzsics
- Institute for Informatics, Ludwig-Maximilians-Universität München, Munich 80333 and Max von Pettenkofer-Institute, Ludwig-Maximilians-Universität München, Munich 80337, Germany
| | - Ulrich H. Koszinowski
- Institute for Informatics, Ludwig-Maximilians-Universität München, Munich 80333 and Max von Pettenkofer-Institute, Ludwig-Maximilians-Universität München, Munich 80337, Germany
| | - Ralf Zimmer
- Institute for Informatics, Ludwig-Maximilians-Universität München, Munich 80333 and Max von Pettenkofer-Institute, Ludwig-Maximilians-Universität München, Munich 80337, Germany
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39
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Polakof S, Rodríguez-Alonso M, Soengas JL. Immunohistochemical localization of glucokinase in rainbow trout brain. Comp Biochem Physiol A Mol Integr Physiol 2009; 153:352-8. [PMID: 19336256 DOI: 10.1016/j.cbpa.2009.03.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2009] [Revised: 03/18/2009] [Accepted: 03/19/2009] [Indexed: 11/28/2022]
Abstract
In mammals, glucosensing neurons reside in brain areas known to play a critical regulatory role in energy homeostasis and neuroendocrine function. In fish, although no glucosensing neurons have been characterized to date, glucokinase (GCK; the main glucosensing marker in mammals) activity and expression were found in hypothalamus and hindbrain of rainbow trout where they related to food intake regulation and glucose homeostasis. However, there are no available studies in literature regarding GCK distribution in brain areas as well as the cell types expressing that protein. In the present study we hypothesize that, as occurs in mammals, GCK would be localized where glucosensing areas have been described. In this sense, we have found GCK immunoreactivity in several areas of trout hypothalamus, of which some of them are related to glucose metabolism, energy homeostasis and food intake, including the lateral hypothalamus, anterior tuberal nucleus, posterior tuberal nucleus and lateral tuberal nucleus. On the other hand, GCKimmunoreactivity was also observed in other areas where the glucosensor system is probably functional,such as the preoptic area and the oculomotor nucleus. Therefore, in this study using immunoreactive techniques, we have demonstrated in those specific areas of the rainbow trout brain previously described as glucosensor the presence of GCK in different cell types.
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Affiliation(s)
- Sergio Polakof
- Laboratorio de Fisioloxía Animal, Facultade de Bioloxía, Universidade de Vigo, 36310 Vigo, Spain.
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40
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The hexokinase gene family in the zebrafish: Structure, expression, functional and phylogenetic analysis. Comp Biochem Physiol B Biochem Mol Biol 2009; 152:189-95. [DOI: 10.1016/j.cbpb.2008.11.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2008] [Revised: 11/26/2008] [Accepted: 11/26/2008] [Indexed: 11/24/2022]
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41
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Expression levels of genes associated with oxygen utilization, glucose transport and glucose phosphorylation in hypoxia exposed Atlantic cod (Gadus morhua). COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2009; 4:128-38. [PMID: 20403769 DOI: 10.1016/j.cbd.2008.12.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2008] [Revised: 12/23/2008] [Accepted: 12/24/2008] [Indexed: 11/23/2022]
Abstract
Expression level of genes associated with oxygen [cytochrome oxidase 1 (COX1) and myoglobin (Mb)] and glucose utilization [glucose transporters (GLUTs) and hexokinases (HKs)] along with metabolic indices were determined in Atlantic cod (Gadus morhua) subjected to an hypoxic challenge of <45% oxygen saturation for 24 days. There were two closely related HKs considered to be homologues of mammalian HKIs. HKIa and HKIb share 86% sequence identity and are both ubiquitously expressed. Mb was also expressed in many tissues with highest levels occurring in heart. Over the first 15 days of hypoxia there were transient increases in plasma lactate in hypoxic relative to normoxic fish associated with a significant decrease in liver glycogen. Over days 1-6, there were in ten of eleven cases, increased average (with a number of conditions being statistically significant) expression levels of GLUTs (1, 2, 4) and HKs (1a and b) in gill, heart, liver, and white muscle in hypoxic relative to normoxic fish. There were significant increases in COX1 and Mb expression levels in gill by day 24 but no changes in these aerobic indicators in heart or liver. Overall the data suggest a transient increase in genes associated with glucose utilization during the early part of the hypoxic challenge followed by alterations in gene expression in gill.
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42
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Rideau N, Berradi H, Skiba-Cassy S, Panserat S, Cailleau-Audouin E, Dupont J. Induction of glucokinase in chicken liver by dietary carbohydrates. Gen Comp Endocrinol 2008; 158:173-7. [PMID: 18662691 DOI: 10.1016/j.ygcen.2008.07.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Revised: 06/26/2008] [Accepted: 07/01/2008] [Indexed: 11/29/2022]
Abstract
We recently provided evidence of the presence of glucokinase (GCK) in the chicken liver [Berradi, H., Taouis, M., Cassy, S., Rideau, N., 2005. Glucokinase in chicken (Gallus gallus). Partial cDNA cloning, immunodetection and activity determination. Comp. Biochem. Physiol. B Biochem. Mol. Biol. 141, 129-139]. In the present study we addressed the question of whether nutritional regulation of GCK occurs. Several nutritional conditions were compared in chickens (5 weeks old) previously trained to meal-feeding. One group was left in the fasted state (F: 24h) and one was tested at the end of the 2h meal (refed: RF). Two other 2h meal-refed groups received an acute oral saccharose load (6ml/kg BW) just before the 2h meal and were sacrificed either at the end of the meal (Saccharose refed, SRF) or 3h later (SRF+3). Liver GCK mRNA and protein levels did not differ between F, RF and SRF chickens but were significantly increased in SRF+3 chickens (2-fold, p<0.05). GCK activity did not differ between F and RF chickens but increased significantly in SRF and SRF+3 chickens (1.7-fold, p<0.05). Chicken liver GCK expression (mRNA and protein) and activity were therefore inducible in these chickens by feeding a meal with acute oral administration of carbohydrate. These and recent findings demonstrating insulin dependency of the liver GCK mRNA and protein strongly suggest that GCK may have an important role in carbohydrate metabolism, including that of the chicken. However, even in these highly stimulatory conditions, liver GCK activity remained relatively low in comparison with other species. The latter result may partly explain the high plasma glucose level in the chicken.
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Affiliation(s)
- Nicole Rideau
- INRA, UR83 Recherches Avicoles, F-37380 Nouzilly, France.
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43
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Clow KA, Ewart KV, Driedzic WR. Low temperature directly activates the initial glycerol antifreeze response in isolated rainbow smelt (Osmerus mordax) liver cells. Am J Physiol Regul Integr Comp Physiol 2008; 295:R961-70. [DOI: 10.1152/ajpregu.90372.2008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Rainbow smelt ( Osmerus mordax) accumulate high levels of glycerol in winter that serve as an antifreeze. Liver glycogen is a source of glycerol during the early stages of glycerol accumulation, whereas dietary glucose and amino acids are essential to maintain rates of glycerol synthesis. We presently report rates of glycerol and glucose production by isolated hepatocytes. Cells from fish held at 0.4 to –1.5°C and incubated at 0.4°C were metabolically quiescent with negligible rates of glycerol or glucose production. Hepatocytes isolated from fish maintained at 8°C and incubated at 8°C produced glucose but not glycerol. Glycerol production was activated in cells isolated from 8°C fish and incubated at 0.4°C without substrate or when glucose, aspartate, or pyruvate was available in the medium. Incubation at 0.4°C without substrate resulted in similar molar rates of glucose and glycerol production in concert with glycogen mobilization. Glycogenolysis and glycerol production were associated with increases in total in vitro activities of glycogen phosphorylase and glycerol-3-phosphate dehydrogenase. Maximal in vitro activities of hexokinase and glucokinase were not influenced by temperature, but high activities of a low- Kmhexokinase may serve to redirect glycogen-derived glucose to glycolysis as opposed to releasing it from the cells. Rates of glycerol production were not enhanced in cells from fish held at 8°C and incubated at 0.4°C with adrenergic or glucocorticoid stimulation. As such, low temperature alone is sufficient to activate the glycerol production mechanism and results in a shift from glucose to a mix of glucose and glycerol production.
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Drew RE, Rodnick KJ, Settles M, Wacyk J, Churchill E, Powell MS, Hardy RW, Murdoch GK, Hill RA, Robison BD. Effect of starvation on transcriptomes of brain and liver in adult female zebrafish (Danio rerio). Physiol Genomics 2008; 35:283-95. [PMID: 18728227 DOI: 10.1152/physiolgenomics.90213.2008] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We used microarray and quantitative real-time PCR (qRT-PCR) analyses in adult female zebrafish (Danio rerio) to identify metabolic pathways regulated by starvation in the liver and brain. The transcriptome of whole zebrafish brain showed little response to 21 days of starvation. Only agouti-related protein 1 (agrp1) significantly responded, with increased expression in brains of starved fish. In contrast, a 21-day period of starvation significantly downregulated 466 and upregulated 108 transcripts in the liver, indicating an overall decrease in metabolic activity, reduced lipid metabolism, protein biosynthesis, proteolysis, and cellular respiration, and increased gluconeogenesis. Starvation also regulated expression of many components of the unfolded protein response, the first such report in a species other than yeast (Saccharomyces cerevisiae) and mice (Mus musculus). The response of the zebrafish hepatic transcriptome to starvation was strikingly similar to that of rainbow trout (Oncorhynchus mykiss) and less similar to mouse, while the response of common carp (Cyprinus carpio) differed considerably from the other three species.
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Affiliation(s)
- Robert E Drew
- Department of Biological Sciences and Initiative for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow
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45
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Polakof S, Míguez JM, Soengas JL. Dietary carbohydrates induce changes in glucosensing capacity and food intake of rainbow trout. Am J Physiol Regul Integr Comp Physiol 2008; 295:R478-89. [DOI: 10.1152/ajpregu.00176.2008] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We hypothesize that variations in dietary carbohydrate levels produce changes in glucosensor parameters in previously characterized glucosensing areas (hypothalamus and hindbrain) related with the regulation of food intake of a carnivorous fish species like rainbow trout. Therefore, we fed trout with standard, carbohydrate-free (CF) or high-carbohydrate (HC) diets for 10 days to assess changes in glucosensing system and food intake. Fish fed CF diet displayed hypoglycemia and increased food intake. Fish fed a HC diet displayed hyperglycemia and decreased food intake. Changes in food intake due to dietary carbohydrates were accompanied in hypothalamus and hindbrain of fish fed with HC diet by changes in parameters involved in glucosensing, such as increased glucose, glucose 6-phosphate, and glycogen levels and increased glucokinase (GK), glycogen synthase, and pyruvate kinase activities as well as increased GK and GLUT2 expression. All those results address for the first time in fish, despite the relative intolerance to glucose of carnivorous species, that dietary carbohydrates are important regulators of the glucosensing system in carnivorous fish, suggesting that the information generated by this system can be associated with the changes observed in food intake.
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Polakof S, Míguez JM, Soengas JL. Changes in food intake and glucosensing function of hypothalamus and hindbrain in rainbow trout subjected to hyperglycemic or hypoglycemic conditions. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2008; 194:829-39. [PMID: 18663455 DOI: 10.1007/s00359-008-0354-y] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2008] [Revised: 06/13/2008] [Accepted: 07/15/2008] [Indexed: 01/10/2023]
Abstract
To evaluate the possible role of glucose in the control of food intake (FI) in fish and the involvement of glucosensing system in that role, we have subjected rainbow trout (via intraperitoneal injections) to control, hyperglycemic (500 mg kg(-1) glucose body mass) or hypoglycemic (4 mg kg(-1) bovine insulin) conditions for 10 days. The experimental design was appropriate since hypoglycemia and hyperglycemia were observed the first 5 days after treatment and changes observed in metabolic parameters in liver were similar to those of fish literature. Hyperglycemic conditions elicited small changes in FI accompanied by increased glucose and glycogen levels, glucokinase (GK) activity and glycolytic potential in hypothalamus and hindbrain. In contrast, hypoglycemic conditions elicited a marked increase in FI accompanied by decreased glucose and glycogen levels and GK activity in the same brain regions whereas both regions displayed different responses in glycolytic potential. These results allow us to hypothesize that, despite the relative intolerance to glucose of carnivorous fish, changes in plasma glucose levels in rainbow trout detected by glucosensing areas in brain regions (hypothalamus and hindbrain) are integrated in those or near areas eliciting a response in FI, which was more important under hypoglycemic than under hyperglycemic conditions.
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Affiliation(s)
- Sergio Polakof
- Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía, Universidade de Vigo, Edificio de Ciencias Experimentais, 36310, Vigo, Spain
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47
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Polakof S, Soengas JL. Involvement of lactate in glucose metabolism and glucosensing function in selected tissues of rainbow trout. J Exp Biol 2008; 211:1075-86. [DOI: 10.1242/jeb.014050] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
The aim of this study was to obtain evidence in rainbow trout for a role of lactate in glucose homeostasis as well as in the function of glucosensing tissues. In a first set of experiments, trout were injected, either (1)intraperitoneally (N=8) with 5 ml kg–1 of Cortland saline alone (control) or saline containing l-(+)-lactate (22.5 mg kg–1 or 45 mg kg–1), oxamate (22.5 mg kg–1) or d-glucose (500 mg kg–1),or (2) intracerebroventricularly (N=11) with 1 μl 100 g–1 body mass of Cortland saline alone (control) or containing d-glucose (400 μg μl–1) or l-(+)-lactate (400 μg μl–1), with samples being obtained 6 h after treatment. In a second set of experiments,hypothalamus, hindbrain and Brockmann bodies were incubated in vitrofor 1 h at 15°C in modified Hanks' medium containing 2, 4 or 8 mmol l–1l-(+)-lactate alone (control) or with 50 mmol l–1 oxamate, 1 mmol l–1 DIDS, 1 mmol l–1 dichloroacetate, 10 mmol l–12-deoxy-d-glucose, 1 mmol l–1α-cyano-4-hydroxy cinnamate or 10 mmol l–1d-glucose. The response of parameters assessed (metabolite levels,enzyme activities and glucokinase expression) in tissues provided evidence for(1) a role for lactate in the regulation of glucose homeostasis through changes not only in brain regions but also in liver energy metabolism, which are further reflected in changes in plasma levels of metabolites; (2) the possible presence in trout brain of an astrocyte–neuron lactate shuttle similar to that found in mammals; and (3) the lack of capacity of lactate to mimic in vitro (but not in vivo) glucose effects in fish glucosensing regions.
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Affiliation(s)
- Sergio Polakof
- Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía,Universidade de Vigo, 36310 Vigo, Spain
| | - José L. Soengas
- Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía,Universidade de Vigo, 36310 Vigo, Spain
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48
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Estey C, Chen X, Moon TW. 3-Hydroxy-3-methylglutaryl coenzyme A reductase in rainbow trout: effects of fasting and statin drugs on activities and mRNA transcripts. Comp Biochem Physiol C Toxicol Pharmacol 2008; 147:386-98. [PMID: 18280795 DOI: 10.1016/j.cbpc.2008.01.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Revised: 12/18/2007] [Accepted: 01/11/2008] [Indexed: 10/22/2022]
Abstract
Human pharmaceuticals including statin drugs are found in effluents post-waste water treatment plant. In order to establish whether statin drugs could affect an aquatic species, we initially characterized in the rainbow trout the enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase or HMGCoAR which is the mammalian target of statin drugs. Two HMGCoAR transcripts (-1 and -2) were isolated to trout tissues and given their prevalence in liver and brain, these two tissues were used in activity assays. HMGCoAR activities were 87.2 and 66.0 pmol/min/mg protein for liver microsomes and whole brain homogenates. Liver activities were affected by conditions promoting phosphorylation but not by a 14 day fast; brain activities were differentially altered by fasting and re-feeding. Even though activities were altered by fasting, HMGCoAR-1 (but not -2) mRNA was reduced by fasting in both the liver and hypothalamus/pituitary. Both statin drugs (cerivastatin and atorvastatin) significantly decreased HMGCoAR activities in vitro and cerivastatin when injected significantly decreased hepatic but not brain activities; some changes in mRNA levels were noted. These studies demonstrate that at the concentrations of statins used in this study, effects on HMGCoAR activities and transcripts occur. Such changes could affect cholesterol content and may alter cholesterol dynamics in this species.
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Affiliation(s)
- Chelsie Estey
- Department of Biology, and Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Ontario, Canada K1N 6N5
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49
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Polakof S, Míguez JM, Soengas JL. In vitro evidences for glucosensing capacity and mechanisms in hypothalamus, hindbrain, and Brockmann bodies of rainbow trout. Am J Physiol Regul Integr Comp Physiol 2007; 293:R1410-20. [PMID: 17567722 DOI: 10.1152/ajpregu.00283.2007] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We aimed to support in vitro the glucosensing capacity observed in vivo in rainbow trout hypothalamus, hindbrain, and Brockmann bodies (BB) and to obtain preliminary evidence of the mechanisms involved. The response of parameters involved in the glucosensing capacity [hexokinase, hexokinase IV (glucokinase), and pyruvate kinase activities and glucose and glycogen levels] was assessed in these tissues incubated for 1 h with 2, 4, or 8 mM d-glucose alone (control) or with specific agonists/inhibitors of the steps involved in glucosensing capacity in mammals. These agents were a competitor for glucose phosphorylation (15 mM mannose), sulfonylurea receptor-1 effectors (500 μM tolbutamide or diazoxide), glycolytic intermediates (15 mM glycerol, lactate, or pyruvate), and inhibitors of glucose transport (10 μM cytochalasin B), glycolysis [20 mM 2-deoxy-d-glucose (2-DG)], and L-type calcium channel (1 μM nifedipine). Control incubations of the three tissues displayed increased glucose and glycogen levels and glucokinase activities in response to increased medium glucose, thus supporting our previous in vivo studies. Furthermore, critical components of the glucosensing mammalian machinery are apparently functioning in the three tissues. The responses in brain regions to all substances tested (except 2-DG and nifedipine) were similar to those observed in mammals, suggesting a similar glucosensing machinery. In contrast, in BB, only the effects of 2-DG, lactate, pyruvate, diazoxide, and nifedipine were similar to those of mammalian β-cells, suggesting that some of the components of the piscine glucosensing model are different than those of mammals. Such differences may relate to the importance of amino acids rather than glucose signaling in the trout BB.
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Affiliation(s)
- Sergio Polakof
- Laboratorio de Fisioloxía Animal, Facultade de Bioloxía, Edificio de Ciencias Experimentais, Universidade de Vigo, E-36310 Vigo, Spain
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50
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Polakof S, Míguez JM, Moon TW, Soengas JL. Evidence for the presence of a glucosensor in hypothalamus, hindbrain, and Brockmann bodies of rainbow trout. Am J Physiol Regul Integr Comp Physiol 2007; 292:R1657-66. [PMID: 17170235 DOI: 10.1152/ajpregu.00525.2006] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aim of this study was to evaluate the existence of a glucosensor in different regions of the brain and in the Brockmann bodies (BB) of the rainbow trout, Oncorhynchus mykiss. Five groups ( n = 12) of trout were injected intraperitoneally with saline alone (control) or saline-containing bovine glucagon (100 μg/kg), bovine insulin (4 mg/kg), 2-deoxy-d-glucose (100 mg/kg), or d-glucose (500 mg/kg) to promote hyperglycemia (glucagon, d-glucose, 2-deoxy-d-glucose) or hypoglycemia (insulin). Six hours after injection, samples from four brain regions (hypothalamus, telencephalon, hindbrain, and midbrain) and the entire BB were taken. Our results demonstrate within the BB and both the hypothalamus and hindbrain a metabolic response different to that observed in other tissues (midbrain, telencephalon) but similar to that described in tissues known to be glucosensors in mammals. The metabolic responses of these areas to changes in plasma glycemia were characterized by parallel changes in GLUT-2 expression, hexokinase-IV, or glucokinase activity and expression, glycolytic potential, and levels of glycogen and glucose. These changes are similar to those reported in mammalian pancreatic β-cells and glucose-excited (GE) neurons, two cell types containing glucosensors. This study provides evidence for the presence of glucosensors responsive to hyper- and hypoglycemia in rainbow trout BB, hypothalamus, and hindbrain.
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Affiliation(s)
- Sergio Polakof
- Laboratorio de Fisioloxía Animal, Facultade de Bioloxía, Edificio de Ciencias Experimentais, Universidade de Vigo, E-36310 Vigo, Spain
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