1
|
Huang KR, Liu QY, Zhang YF, Luo YL, Fu C, Pang X, Fu SJ. Whether hypoxia tolerance improved after short-term fasting is closely related to phylogeny but not to foraging mode in freshwater fish species. J Comp Physiol B 2024:10.1007/s00360-024-01588-8. [PMID: 39347810 DOI: 10.1007/s00360-024-01588-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 09/04/2024] [Accepted: 09/15/2024] [Indexed: 10/01/2024]
Abstract
The combined stresses of fasting and hypoxia are common events during the life history of freshwater fish species. Hypoxia tolerance is vital for survival in aquatic environments, which requires organisms to down-regulate their maintenance energetic expenditure while simultaneously preserving physiological features such as oxygen supply capacity under conditions of food deprivation. Generally, infrequent-feeding species who commonly experience food shortages might evolve more adaptive strategies to cope with food deprivation than frequent-feeding species. Thus, the present study aimed to test whether the response of hypoxia tolerance in fish to short-term fasting (2 weeks) varied with different foraging modes. Fasting resulted in similar decreases in maintenance energetic expenditure and similar decreases in Pcrit and Ploe between fishes with different foraging modes, whereas it resulted in decreased oxygen supply capacity only in frequent-feeding fishes. Furthermore, independent of foraging mode, fasting decreased Pcrit and Ploe in all Cypriniformes and Siluriformes species but not in Perciformes species. The mechanism for decreased Pcrit and Ploe in Cypriniformes and Siluriformes species is at least partially due to the downregulated metabolic demand and/or the maintenance of a high oxygen supply capacity while fasting. The present study found that the effect of fasting on hypoxia tolerance depends upon phylogeny in freshwater fish species. The information acquired in the present study is highly valuable in aquaculture industries and can be used for species conservation in the field.
Collapse
Affiliation(s)
- Ke-Ren Huang
- Laboratory of Evolutionary Physiology and Behavior, Chongqing Key Laboratory of Conservation and Utilization of Freshwater Fishes, Animal Biology Key Laboratory of Chongqing Education Commission of China, Chongqing Normal University, Chongqing, 401331, China
| | - Qian-Ying Liu
- Laboratory of Evolutionary Physiology and Behavior, Chongqing Key Laboratory of Conservation and Utilization of Freshwater Fishes, Animal Biology Key Laboratory of Chongqing Education Commission of China, Chongqing Normal University, Chongqing, 401331, China
| | - Yong-Fei Zhang
- Laboratory of Evolutionary Physiology and Behavior, Chongqing Key Laboratory of Conservation and Utilization of Freshwater Fishes, Animal Biology Key Laboratory of Chongqing Education Commission of China, Chongqing Normal University, Chongqing, 401331, China
| | - Yu-Lian Luo
- Laboratory of Evolutionary Physiology and Behavior, Chongqing Key Laboratory of Conservation and Utilization of Freshwater Fishes, Animal Biology Key Laboratory of Chongqing Education Commission of China, Chongqing Normal University, Chongqing, 401331, China
| | - Cheng Fu
- Laboratory of Evolutionary Physiology and Behavior, Chongqing Key Laboratory of Conservation and Utilization of Freshwater Fishes, Animal Biology Key Laboratory of Chongqing Education Commission of China, Chongqing Normal University, Chongqing, 401331, China
| | - Xu Pang
- College of Fisheries, Southwest University, Chongqing, 400715, China
| | - Shi-Jian Fu
- Laboratory of Evolutionary Physiology and Behavior, Chongqing Key Laboratory of Conservation and Utilization of Freshwater Fishes, Animal Biology Key Laboratory of Chongqing Education Commission of China, Chongqing Normal University, Chongqing, 401331, China.
| |
Collapse
|
2
|
Zaitoon H, Yackobovitch-Gavan M, Midlej E, Uretzky A, Laurian I, Dorfman A, Interator H, Lebenthal Y, Brener A. The role of IGF1 in determining body composition in children and adolescents with growth hormone deficiency and those with idiopathic short stature. Endocrine 2024:10.1007/s12020-024-03992-0. [PMID: 39143422 DOI: 10.1007/s12020-024-03992-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Accepted: 08/02/2024] [Indexed: 08/16/2024]
Abstract
PURPOSE Treatment with recombinant human growth hormone (rhGH) increases insulin growth factor-1 (IGF1) levels, therefore, monitoring both IGF1 and growth constitutes an acceptable parameter of therapeutic safety and efficacy. We aimed to investigate the relationship between IGF1 level and body composition in children and adolescents undergoing rhGH therapy for growth hormone deficiency (GHD) and idiopathic short stature (ISS). METHODS This observational retrospective study included the bioimpedance analysis (BIA) reports (n = 305) of 135 pediatric patients (age 5-18 years), 64 with GHD and 71 with ISS, conducted as part of routine clinic visits. Sociodemographic and clinical data were extracted from medical records. Generalized estimating equations linear models were used to explore the contributing factors for body composition components of fat percentage (FATP), appendicular skeletal muscle mass (ASMM) z-score, and muscle-to-fat ratio (MFR) z-score while adjusting for cumulative doses of rhGH. RESULTS Subjects with GHD exhibited higher body mass index z-scores (p < 0.001), higher FATP and truncal FATP scores, lower MFR z-score, and higher diastolic blood pressure percentiles than the ISS group (p = 0.010, p = 0.027, p = 0.050, and p = 0.050, respectively). Female sex (p < 0.001) and a GHD diagnosis (p < 0.001), were major contributors to higher FATP scores; female sex (p = 0.049) and ISS diagnosis (p = 0.005) were major contributors to higher MFR z-scores; and female sex (p < 0.001), older age (p < 0.001) and higher insulin-like growth factor 1 z-scores (p = 0.021) were major contributors to higher ASMM z-scores. Socioeconomic position and cumulative rhGH dose were not significant contributors to body composition parameters. CONCLUSION Children with GHD, including those undergoing rhGH treatment, may be at risk for increased adiposity and associated metabolic implications. Sex- and age-adjusted IGF1 levels were related to muscle mass but not to adiposity. Hence, rhGH treatment aimed at increasing IGF1 levels may alleviate these effects by promoting muscle growth.
Collapse
Affiliation(s)
- Hussein Zaitoon
- The Institute of Pediatric Endocrinology, Diabetes and Metabolism, Dana-Dwek Children's Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Michal Yackobovitch-Gavan
- Department of Epidemiology and Preventive Medicine, School of Public Health, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Eyas Midlej
- The Institute of Pediatric Endocrinology, Diabetes and Metabolism, Dana-Dwek Children's Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Adi Uretzky
- The Institute of Pediatric Endocrinology, Diabetes and Metabolism, Dana-Dwek Children's Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Irina Laurian
- The Institute of Pediatric Endocrinology, Diabetes and Metabolism, Dana-Dwek Children's Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Anna Dorfman
- The Institute of Pediatric Endocrinology, Diabetes and Metabolism, Dana-Dwek Children's Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Hagar Interator
- The Institute of Pediatric Endocrinology, Diabetes and Metabolism, Dana-Dwek Children's Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Yael Lebenthal
- The Institute of Pediatric Endocrinology, Diabetes and Metabolism, Dana-Dwek Children's Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Avivit Brener
- The Institute of Pediatric Endocrinology, Diabetes and Metabolism, Dana-Dwek Children's Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
| |
Collapse
|
3
|
Li W, Li H, Hu Q, Wang L, Yin Z, Hu G. IGFBP1a is a nutrient deficient response factor that can inhibit fish reproduction through the hypothalamus-pituitary-ovary axis†. Biol Reprod 2024; 110:761-771. [PMID: 38374691 DOI: 10.1093/biolre/ioae009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 11/27/2023] [Accepted: 01/09/2024] [Indexed: 02/21/2024] Open
Abstract
Reproduction is a high energy consuming process, so long-term malnutrition can significantly inhibit gonadal development. However, little is known about the molecular mechanism by which fasting inhibits reproduction. Our present study found that fasting could dramatically induce insulin-like growth factor binding protein 1 (IGFBP1) expression in the liver, hypothalamus, pituitary and ovaries of grass carp. In addition, IGFBP1a in the hypothalamus-pituitary-gonad axis could inhibit the development of gonads. These results indicated that fasting may participate in the regulation of fish gonadal development through the mediation of IGFBP1a. Further studies found that IGFBP1a could markedly inhibit gonadotropin-releasing hormone 3 expressions in hypothalamus cells. At the pituitary level, IGFBP1a could significantly reduce the gonadotropin hormones (LH and FSH) expression by blocking the action of pituitary insulin-like growth factor 1. Interestingly, IGFBP1a could also directly inhibit the expression of lhr, fshr, and sex steroid hormone synthase genes (cyp11a, cyp17a, and cyp19a1) in the ovary. These results indicated that IGFBP1a should be a nutrient deficient response factor that could inhibit fish reproduction through the hypothalamus-pituitary-ovary axis.
Collapse
Affiliation(s)
- Wei Li
- Hubei Hongshan Laboratory, College of Fisheries, Huazhong Agricultural University, Wuhan, China
| | - Hangyu Li
- Hubei Hongshan Laboratory, College of Fisheries, Huazhong Agricultural University, Wuhan, China
| | - Qiongyao Hu
- Hubei Hongshan Laboratory, College of Fisheries, Huazhong Agricultural University, Wuhan, China
| | - Linlin Wang
- Hubei Hongshan Laboratory, College of Fisheries, Huazhong Agricultural University, Wuhan, China
| | - Zhan Yin
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Guangfu Hu
- Hubei Hongshan Laboratory, College of Fisheries, Huazhong Agricultural University, Wuhan, China
| |
Collapse
|
4
|
Zou X, Liu Q, Guan Q, Zhao M, Zhu X, Pan Y, Liu L, Gao Z. Muscle Fiber Characteristics and Transcriptome Analysis in Slow- and Fast-Growing Megalobrama amblycephala. Genes (Basel) 2024; 15:179. [PMID: 38397169 PMCID: PMC10888202 DOI: 10.3390/genes15020179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Revised: 01/25/2024] [Accepted: 01/26/2024] [Indexed: 02/25/2024] Open
Abstract
Growth is an important trait in aquaculture that is influenced by various factors, among which genetic regulation plays a crucial role. Megalobrama amblycephala, one of the most important freshwater species in China, exhibits wide variations in body mass among individuals of the same age within the same pool. But the molecular mechanisms underlying wide variation in body mass remain unclear. Here, we performed muscle histological and transcriptome analysis of muscle tissues from Fast-Growing (FG) and Slow-Growing (SG) M. amblycephala at the age of 4 months old (4 mo) and 10 months old (10 mo) to elucidate its muscle development and growth mechanism. The muscle histological analysis showed smaller diameter and higher total number of muscle fibers in FG compared to SG at 4 mo, while larger diameter and total number of muscle fibers were detected in FG at 10 mo. The transcriptome analysis of muscle tissue detected 1171 differentially expressed genes (DEGs) between FG and SG at 4 mo, and 718 DEGs between FG and SG at 10 mo. Furthermore, 44 DEGs were consistently up-regulated in FG at both 4 mo and 10 mo. Up-regulated DEGs in FG at 4 mo were mainly enriched in the pathways related to cell proliferation, while down-regulated DEGs were significantly enriched in cell fusion and muscle contraction. Up-regulated DEGs in FG at 10 mo were mainly enriched in the pathways related to cell proliferation and protein synthesis. Therefore, these results provide novel insights into the molecular mechanism of M. amblycephala muscle growth at different stages, and will be of great guiding significance to promote the fast growth of M. amblycephala.
Collapse
Affiliation(s)
- Xue Zou
- Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; (X.Z.); (Q.L.); (Q.G.); (M.Z.); (Z.G.)
| | - Qi Liu
- Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; (X.Z.); (Q.L.); (Q.G.); (M.Z.); (Z.G.)
| | - Qianqian Guan
- Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; (X.Z.); (Q.L.); (Q.G.); (M.Z.); (Z.G.)
| | - Ming Zhao
- Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; (X.Z.); (Q.L.); (Q.G.); (M.Z.); (Z.G.)
| | - Xin Zhu
- Department of Bioengineering and Environmental Science, Changsha University, Changsha 410003, China; (X.Z.)
| | - Yaxiong Pan
- Department of Bioengineering and Environmental Science, Changsha University, Changsha 410003, China; (X.Z.)
| | - Lusha Liu
- Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; (X.Z.); (Q.L.); (Q.G.); (M.Z.); (Z.G.)
| | - Zexia Gao
- Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; (X.Z.); (Q.L.); (Q.G.); (M.Z.); (Z.G.)
- Hubei Hongshan Laboratory, Wuhan 430070, China
- Engineering Technology Research Center for Fish Breeding and Culture in Hubei Province, Wuhan 430070, China
| |
Collapse
|
5
|
Bersin TV, Cordova KL, Journey ML, Beckman BR, Lema SC. Food deprivation reduces sensitivity of liver Igf1 synthesis pathways to growth hormone in juvenile gopher rockfish (Sebastes carnatus). Gen Comp Endocrinol 2024; 346:114404. [PMID: 37940008 DOI: 10.1016/j.ygcen.2023.114404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 10/19/2023] [Accepted: 11/03/2023] [Indexed: 11/10/2023]
Abstract
Growth hormone (Gh) regulates growth in part by stimulating the liver to synthesize and release insulin-like growth factor-1 (Igf1), which then promotes somatic growth. However, for fish experiencing food limitation, elevated blood Gh can occur even with low circulating Igf1 and slow growth, suggesting that nutritional stress can alter the sensitivity of liver Igf1 synthesis pathways to Gh. Here, we examined how recent feeding experience affected Gh regulation of liver Igf1 synthesis pathways in juvenile gopher rockfish (Sebastes carnatus) to illuminate mechanisms underlying the nutritional modulation of Igf1 production. Juvenile gopher rockfish were maintained under conditions of feeding or complete food deprivation (fasting) for 14 d and then treated with recombinant sea bream (Sparus aurata) Gh or saline control. Gh upregulated hepatic igf1 mRNA levels in fed fish but not in fasted fish. The liver of fasted rockfish also showed a lower relative abundance of gene transcripts encoding teleost Gh receptors 1 (ghr1) and 2 (ghr2), as well as reduced protein levels of phosphorylated janus tyrosine kinase 2 (pJak2) and signal transducer and activator of transcription 5 (pStat5), which function to induce igf1 gene transcription following Gh binding to Gh receptors. Relative hepatic mRNA levels for suppressors of cytokine signaling (Socs) genes socs2, socs3a, and socs3b were also lower in fasted rockfish. Socs2 can suppress Gh activation of Jak2/Stat5, and fasting-related variation in socs expression may reflect modulated inhibitory control of igf1 gene transcription. Fasted rockfish also had elevated liver mRNA abundances for lipolytic hormone-sensitive lipase 1 (hsl1) and Igf binding proteins igfbp1a, -1b and -3a, reduced liver mRNAs encoding igfbp2b and an Igfbp acid labile subunit-like (igfals) gene, and higher transcript abundances for Igf1 receptors igf1ra and igf1rb in skeletal muscle. Together, these findings suggest that food deprivation impacts liver Igf1 responsiveness to Gh via multiple mechanisms that include a downregulation of hepatic Gh receptors, modulation of the intracellular Jak2/Stat5 transduction pathway, and possible shifts in Socs-inhibitory control of igf1 gene transcription, while also demonstrating that these changes occur in concert with shifts in liver Igfbp expression and muscle Gh/Igf1 signaling pathway components.
Collapse
Affiliation(s)
- Theresa V Bersin
- Biological Sciences Department, Center for Coastal Marine Sciences, California Polytechnic State University, San Luis Obispo, CA 93407, USA
| | - Kasey L Cordova
- Biological Sciences Department, Center for Coastal Marine Sciences, California Polytechnic State University, San Luis Obispo, CA 93407, USA
| | - Meredith L Journey
- Lynker Technology, 202 Church St SE #536, Leesburg, VA 20175, USA; Under Contract to Environmental and Fisheries Sciences Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA 98112, USA
| | - Brian R Beckman
- Environmental and Fisheries Sciences Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA 98112, USA
| | - Sean C Lema
- Biological Sciences Department, Center for Coastal Marine Sciences, California Polytechnic State University, San Luis Obispo, CA 93407, USA.
| |
Collapse
|
6
|
Mitra A, Shanavas S, Chaudhury D, Bose B, Das UN, Shenoy P S. Mitigation of chronic glucotoxicity-mediated skeletal muscle atrophy by arachidonic acid. Life Sci 2023; 333:122141. [PMID: 37797688 DOI: 10.1016/j.lfs.2023.122141] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Revised: 09/27/2023] [Accepted: 10/01/2023] [Indexed: 10/07/2023]
Abstract
Toxicity caused by chronic hyperglycemia is a significant factor affecting skeletal muscle myogenesis, resulting in diabetic myopathy. Chronic and persistent hyperglycemia causes activation of the atrophy-related pathways in the skeletal muscles, which eventually results in inflammation and muscle degeneration. To counteract this process, various bioactive compound has been studied for their reversal or hypertrophic effect. In this study, we explored the molecular mechanisms associated with reversing glucotoxicity's effect in C2C12 cells by arachidonic acid (AA). We found a substantial increase in the pro-inflammatory cytokines and ROS production in hyperglycemic conditions, mitigated by AA supplementation. We found that AA supplementation restored protein synthesis that was downregulated under glucotoxicity conditions. AA enhanced myogenesis by suppressing high glucose induced inflammation and ROS production and enhancing protein synthesis. These results imply that AA has cytoprotective actions against hyperglycemia-induced cytotoxicity.
Collapse
Affiliation(s)
- Akash Mitra
- Stem Cells and Regenerative Medicine Centre, Yenepoya Research Centre, Yenepoya Deemed to be University, University Road, Deralakatte, Mangalore 575018, Karnataka, India
| | - Shanooja Shanavas
- Stem Cells and Regenerative Medicine Centre, Yenepoya Research Centre, Yenepoya Deemed to be University, University Road, Deralakatte, Mangalore 575018, Karnataka, India
| | - Debajit Chaudhury
- Stem Cells and Regenerative Medicine Centre, Yenepoya Research Centre, Yenepoya Deemed to be University, University Road, Deralakatte, Mangalore 575018, Karnataka, India
| | - Bipasha Bose
- Stem Cells and Regenerative Medicine Centre, Yenepoya Research Centre, Yenepoya Deemed to be University, University Road, Deralakatte, Mangalore 575018, Karnataka, India
| | - Undurti N Das
- UND Life Sciences, 2221 NW 5(th) St, Battle Ground, WA 98604, USA; Department of Biotechnology, Indian Institute of Technology-Hyderabad, Telangana, India; Department of Medicine, Omega Hospitals, Gachibowli, Hyderabad, 500032, India
| | - Sudheer Shenoy P
- Stem Cells and Regenerative Medicine Centre, Yenepoya Research Centre, Yenepoya Deemed to be University, University Road, Deralakatte, Mangalore 575018, Karnataka, India.
| |
Collapse
|
7
|
Bersin TV, Mapes HM, Journey ML, Beckman BR, Lema SC. Insulin-like growth factor-1 (Igf1) signaling responses to food consumption after fasting in the Pacific rockfish Sebastes carnatus. Comp Biochem Physiol A Mol Integr Physiol 2023; 282:111444. [PMID: 37201654 DOI: 10.1016/j.cbpa.2023.111444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 05/12/2023] [Accepted: 05/13/2023] [Indexed: 05/20/2023]
Abstract
Fish adjust rates of somatic growth in the face of changing food consumption. As in other vertebrates, growth in fish is regulated by the growth hormone (Gh)/insulin-like growth factor-1 (Igf1) endocrine axis, and changes in food intake impact growth via alterations to Gh/Igf1 signaling. Understanding the time course by which the Gh/Igf1 axis responds to food consumption is crucial to predict how rapidly changes in food abundance might lead to altered growth dynamics. Here, we looked at the response times of plasma Igf1 and liver Igf1 signaling-associated gene expression to refeeding after food deprivation in juvenile gopher rockfish (Sebastes carnatus), one of several species of northern Pacific Ocean Sebastes rockfishes targeted by fisheries or utilized for aquaculture. Gopher rockfish were fasted for 30 d, after which a subset was fed to satiation for 2 h, while other rockfish continued to be fasted. Refed fish exhibited higher hepatosomatic index (HSI) values and increased Igf1 after food consumption. Gene transcripts for Gh receptor 1 (ghr1), but not ghr2, increased in the liver after eating. Transcripts encoding igf1 also increased in the liver of refed fish 2-4 d after feeding, only to return to levels similar as continually fasted rockfish by 9 d after feeding. Liver mRNA abundances for Igf binding protein (Igfbp) genes igfbp1a, igfbp1b, and igfbp3a declined within 2 d of feeding. These findings provide evidence that circulating Igf1 in rockfish reflects a fish's feeding experience within the previous few days, and suggest that feeding-induced increases in Igf1 are being mediated in part by altered liver sensitivity to Gh due to upregulated Gh receptor 1 expression.
Collapse
Affiliation(s)
- Theresa V Bersin
- Biological Sciences Department, Center for Coastal Marine Sciences, California Polytechnic State University, San Luis Obispo, CA 93407, USA
| | - Hayley M Mapes
- Biological Sciences Department, Center for Coastal Marine Sciences, California Polytechnic State University, San Luis Obispo, CA 93407, USA
| | - Meredith L Journey
- Lynker Technology, 202 Church St SE #536, Leesburg, VA 20175, USA; Under Contract to Environmental and Fisheries Sciences Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA 98112, USA
| | - Brian R Beckman
- Environmental and Fisheries Sciences Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA 98112, USA
| | - Sean C Lema
- Biological Sciences Department, Center for Coastal Marine Sciences, California Polytechnic State University, San Luis Obispo, CA 93407, USA.
| |
Collapse
|