scholarly journals Metabolic hormones regulate basal and growth hormone-dependent igf2 mRNA level in primary cultured coho salmon hepatocytes: effects of insulin, glucagon, dexamethasone, and triiodothyronine

2009 ◽  
Vol 204 (3) ◽  
pp. 331-339 ◽  
Author(s):  
A L Pierce ◽  
J T Dickey ◽  
L Felli ◽  
P Swanson ◽  
W W Dickhoff
Keyword(s):  
Growth Hormone ◽  
Coho Salmon ◽  
Mrna Level ◽  
Postnatal Growth ◽  
Mrna Levels ◽  
Growth Physiology ◽  
Metabolic Hormones ◽  
Synergistic Regulation ◽  
Growth Promoting ◽  
Stimulation Of

Igf1 and Igf2 stimulate growth and development of vertebrates. Circulating Igfs are produced by the liver. In mammals, Igf1 mediates the postnatal growth-promoting effects of growth hormone (Gh), whereas Igf2 stimulates fetal and placental growth. Hepatic Igf2 production is not regulated by Gh in mammals. Little is known about the regulation of hepatic Igf2 production in nonmammalian vertebrates. We examined the regulation of igf2 mRNA level by metabolic hormones in primary cultured coho salmon hepatocytes. Gh, insulin, the glucocorticoid agonist dexamethasone (Dex), and glucagon increased igf2 mRNA levels, whereas triiodothyronine (T3) decreased igf2 mRNA levels. Gh stimulated igf2 mRNA at physiological concentrations (0.25×10−9 M and above). Insulin strongly enhanced Gh stimulation of igf2 at low physiological concentrations (10−11 M and above), and increased basal igf2 (10−8 M and above). Dex stimulated basal igf2 at concentrations comparable to those of stressed circulating cortisol (10−8 M and above). Glucagon stimulated basal and Gh-stimulated igf2 at supraphysiological concentrations (10−7 M and above), whereas T3 suppressed basal and Gh-stimulated igf2 at the single concentration tested (10−7 M). These results show that igf2 mRNA level is highly regulated in salmon hepatocytes, suggesting that liver-derived Igf2 plays a significant role in salmon growth physiology. The synergistic regulation of igf2 by insulin and Gh in salmon hepatocytes is similar to the regulation of hepatic Igf1 production in mammals.

scholarly journals Differential regulation of Igf1 and Igf2 mRNA levels in tilapia hepatocytes: effects of insulin and cortisol on GH sensitivity

2011 ◽  
Vol 211 (2) ◽  
pp. 201-210 ◽  
Author(s):  
Andrew L Pierce ◽  
Jason P Breves ◽  
Shunsuke Moriyama ◽  
Tetsuya Hirano ◽  
E Gordon Grau
Keyword(s):  
Growth And Development ◽  
Mrna Level ◽  
Differential Regulation ◽  
Postnatal Life ◽  
Mrna Levels ◽  
Primary Cultured Hepatocytes ◽  
Mammalian Liver ◽  
Growth Promoting ◽  
Stimulation Of

Igf1 and Igf2 stimulate growth and development of vertebrates. In mammals, liver-derived endocrine Igf1 mediates the growth promoting effects of GH during postnatal life, whereas Igf2 stimulates placental and fetal growth and is not regulated by GH. Insulin enhances Igf1 production by the mammalian liver directly, and by increasing hepatocyte sensitivity to GH. We examined the regulation ofigf1andigf2mRNA levels by GH, insulin, and cortisol, and the effects of insulin and cortisol on GH sensitivity in primary cultured hepatocytes of tilapia, a cichlid teleost. GH increased mRNA levels of bothigf1andigf2in a concentration-related and biphasic manner over the physiological range, with a greater effect onigf2mRNA level. Insulin increased basaligf2mRNA level, and strongly increased GH-stimulatedigf2mRNA level, but slightly reduced basaligf1mRNA level and did not affect GH-stimulatedigf1mRNA level. Cortisol inhibited GH stimulation ofigf1, but increased GH stimulation ofigf2mRNA level. The synergistic effect of insulin and GH onigf2mRNA level was confirmedin vivo. These results indicate that insulin and cortisol differentially modulate the response ofigf1andigf2mRNA to GH in tilapia hepatocytes, and suggest that the regulation of liver Igf2 production differs between fish and mammals. Regulation of liver Igf2 production in fish appears to be similar to regulation of liver Igf1 production in mammals.

scholarly journals Regulation of angiopoietin-like protein 4/fasting-induced adipose factor (Angptl4/FIAF) expression in mouse white adipose tissue and 3T3-L1 adipocytes

2008 ◽  
Vol 100 (1) ◽  
pp. 18-26 ◽  
Author(s):  
Sarah Dutton ◽  
Paul Trayhurn
Keyword(s):  
Skeletal Muscle ◽  
Cell Culture ◽  
Adipose Tissue ◽  
White Adipose Tissue ◽  
Culture Medium ◽  
Mrna Level ◽  
Mrna Levels ◽  
Rt Pcr ◽  
Before And After ◽  
Stimulation Of

Angiopoietin-like protein 4 (Angptl4)/FIAF (fasting-induced adipose factor) was first identified as a target for PPAR and to be strongly induced in white adipose tissue (WAT) by fasting. Here we have examined the regulation of the expression and release of this adipokine in mouse WAT and in 3T3-L1 adipocytes. Angptl4/FIAF expression was measured by RT-PCR and real-time PCR; plasma Angptl4/FIAF and release of the protein in cell culture was determined by western blotting. The Angptl4/FIAF gene was expressed in each of the major WAT depots of mice, the mRNA level in WAT being similar to the liver and much higher (>50-fold) than skeletal muscle. Fasting mice (18 h) resulted in a substantial increase in Angptl4/FIAF mRNA in liver and muscle (9·5- and 21-fold, respectively); however, there was no effect of fasting on Angptl4/FIAF mRNA in WAT and the plasma level of Angptl4/FIAF was unchanged. The Angptl4/FIAF gene was expressed in 3T3-L1 adipocytes before and after differentiation, the level increasing post-differentiation; Angptl4/FIAF was released into the culture medium. Insulin, leptin, dexamethasone, noradrenaline, TNFα and several IL (IL-1β, IL-6, IL-10, IL-18) had little effect on Angptl4/FIAF mRNA levels in 3T3-L1 adipocytes. However, a major stimulation of Angptl4/FIAF expression was observed with rosiglitazone and the inflammatory prostaglandins PGD2 and PGJ2. Angptl4/FIAF does not act as an adipose tissue signal of nutritional status, but is markedly induced by fasting in liver and skeletal muscle.

scholarly journals Metabolic hormones modulate the effect of growth hormone (GH) on insulin-like growth factor-I (IGF-I) mRNA level in primary culture of salmon hepatocytes

2005 ◽  
Vol 184 (2) ◽  
pp. 341-349 ◽  
Author(s):  
A L Pierce ◽  
H Fukada ◽  
W W Dickhoff
Keyword(s):  
Growth Hormone ◽  
Growth Factor ◽  
Primary Culture ◽  
Growth Regulation ◽  
Mrna Level ◽  
Insulin Like Growth Factor ◽  
Metabolic Hormones ◽  
Factor I ◽  
Igf I ◽  
Gh Resistance

Liver production of insulin-like growth factor-I (IGF-I) is a major point of control in the growth hormone (GH)/IGF axis, the endocrine system regulating body growth in fishes and other vertebrates. Pituitary GH stimulates hepatocyte production of IGF-I; however, in catabolic states, hepatocyte GH resistance results in decreases in liver IGF-I production. To investigate endocrine mechanisms leading to the development of hepatocyte GH resistance, we examined the regulation of IGF-I mRNA level by GH and metabolic hormones in primary culture of salmon hepatocytes. Cells were cultured in RPMI medium, and exposed to insulin (Ins, 10−6 M), glucagon (Glu, 10−6 M), triiodothyronine (T3, 10−7 M), dexamethasone (Dex, 10−6 M) and glucagon-like peptide (GLP, 10−6 M), in the presence and absence of GH (5×10−9 M). GH always increased IGF-I mRNA. None of the other hormones tested alone affected IGF-I mRNA. However, Dex, Ins and Glu reduced the response to GH. The response to GH was inhibited by Dex at concentrations of 10−12 M and above, by Ins at 10−9 M and above, and by Glu only at 10−6 M. Inhibition of GH response by glucocorticoids is found in other vertebrates. Salmon hepatocytes were very sensitive to Dex, suggesting that glucocorticoids may play an important role in salmon growth regulation even in unstressed conditions. Inhibition of GH response by Ins is the opposite of what is found in mammals and chickens, suggesting that the role of Ins in growth regulation may differ between fishes and tetrapods. To examine mechanisms for modulation of GH sensitivity, we measured hepatocyte GH receptor (GHR) mRNA levels. Ins inhibited and Dex stimulated GHR mRNA, suggesting that different mechanisms mediate the inhibition of GH response by these hormones. This study shows that glucocorticoids, Ins, and Glu induce GH resistance in cultured salmon hepatocytes.

scholarly journals Growth hormone transgenesis disrupts immune function in muscle of coho salmon (Oncorhynchus kisutch) impacting cross-talk with growth systems

2017 ◽  
Author(s):  
Abdullah Alzaid ◽  
Jin-Hyoung Kim ◽  
Robert H. Devlin ◽  
Samuel A.M. Martin ◽  
Daniel J. Macqueen
Keyword(s):  
Growth Hormone ◽  
Immune Function ◽  
Cross Talk ◽  
Coho Salmon ◽  
Mrna Level ◽  
Muscle Growth ◽  
Oncorhynchus Kisutch ◽  
Marker Genes ◽  
Wild Type ◽  
Igf System

ABSTRACTThe suppression of growth during infection should facilitate resource allocation towards effective immune function. Work supporting this hypothesis has been recently reported in teleosts, demonstrating immune-responsive regulation of the insulin-like growth factor (IGF) system - a key endocrine growth pathway that acts downstream of growth hormone (GH). Skeletal muscle is the main target for growth and energetic storage in fish, yet little is known about how growth is regulated in this tissue during an immune response. We addressed this knowledge gap by characterizing muscle immune responses in size-matched coho salmon (Oncorhynchus kisutch) achieving different growth rates. We compared a wild-type strain with two GH transgenic groups achieving either maximal or highly-suppressed growth – an experimental design that separates GH’s direct effects from its influence on growth rate. Fish were sampled 30h post-injection with PBS (control) or mimics of bacterial (peptidoglycan) or viral (Poly:IC) infection. We quantified the mRNA level expression of genes from the GH, GH receptor (GHR), IGF hormone, IGF1 receptor (IGF-1R) and IGF binding protein (IGFBP) families, along with marker genes for muscle growth and host defence genes involved in inflammatory or antiviral responses. We provide strong evidence for dampened immunity in the GH transgenics compared to wild-type animals. Strikingly, the muscle of GH transgenics achieving rapid growth showed no detectable antiviral response, coupled with evidence of a constitutive inflammatory state. GH and IGF system gene expression was also strongly altered by GH transgenesis and fast growth, both for baseline expression levels and responses to immune stimulation. Overall, our findings demonstrate that GH transgenesis disrupts normal immune function and growth-immune cross-talk in muscle, with implications for the health and welfare of farmed salmon.

scholarly journals myo-Inositol is an osmolyte in rat liver macrophages (Kupffer cells) but not in RAW 264.7 mouse macrophages

1997 ◽  
Vol 326 (1) ◽  
pp. 289-295 ◽  
Author(s):  
Ulrich WARSKULAT ◽  
Christian WEIK ◽  
Dieter HÄUSSINGER
Keyword(s):  
Rat Liver ◽  
Kupffer Cells ◽  
Mrna Level ◽  
Raw 264.7 ◽  
Mrna Levels ◽  
Mouse Macrophages ◽  
Taurine Uptake ◽  
Inositol Uptake ◽  
Stimulation Of

The role of myo-inositol as an osmolyte was studied in cultured rat liver macrophages (Kupffer cells). Hyperosmotic exposure of Kupffer cells stimulated myo-inositol uptake and led to an increase in the mRNA levels for the sodium/myo-inositol co-transporter (SMIT). Conversely, hypo-osmotic (205 m-osM) exposure diminished myo-inositol uptake when compared with normo-osmotic (305 m-osM) control incubations. The hyperosmolarity-induced SMIT mRNA increase was counteracted by added myo-inositol or betaine. In contrast with Kupffer cells, there was only a slight hyperosmotic stimulation of myo-inositol uptake in RAW 264.7 mouse macrophages, and the myo-inositol transporter (SMIT) mRNA was not detectable. Further, a slight stimulation of taurine uptake and an increase in taurine transporter (TAUT) mRNA level by hyperosmolarity was observed in RAW 264.7 cells, whereas hypo-osmolarity led to a decrease in taurine uptake and TAUT mRNA level. When Kupffer cells were preloaded with myo-inositol, hypo-osmotic exposure led to a rapid efflux of myo-inositol from the cells. Myo-inositol efflux was also stimulated by phagocytosis of latex particles; however, latex was without effect on the hyperosmolarity-induced increase of SMIT mRNA levels. The results suggest a role of myo-inositol as an osmolyte in rat Kupffer cells but not in RAW 264.7 mouse macrophages. The functional relevance of this osmolyte strategy might lie in the maintenance of cell volume homeostasis during phagocytosis in Kupffer cells; however, the interplay with the other osmolytes betaine and taurine remains to be established.

Hexarelin Stimulation of Growth Hormone Release and mRNA Levels in an Infant and Adult Rat Model of Impaired GHRH Function

1997 ◽  
Vol 65 (2) ◽  
pp. 91-97 ◽  
Author(s):  
Antonio Torsello ◽  
Marina Luoni ◽  
Roberta Grilli ◽  
Margherita Guidi ◽  
William B. Wehrenberg ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Rat Model ◽  
Mrna Levels ◽  
Hormone Release ◽  
Growth Hormone Release ◽  
Adult Rat ◽  
Stimulation Of

PSII-B-25 Age-related changes in growth hormone-insulin like growth factor 1 axis-regulating factors and metabolic hormones in Korean cattle steer

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 350-351
Author(s):  
Jinoh Lee ◽  
Seok-Hyeon Beak ◽  
Do Hyun Kim ◽  
Jae Sung Lee ◽  
In Gu Cho ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Growth Factor ◽  
Muscle Fiber ◽  
Mrna Levels ◽  
Meat Yield ◽  
Metabolic Hormones ◽  
Korean Cattle ◽  
Age Related ◽  
Fiber Size ◽  
Age Related Changes

Abstract Meat yield is important for beef industry for maximum profits. Enhancing muscle growth by promoting hypertrophy of muscle fiber is required for increasing meat yield. Growth hormone (GH)-insulin like growth factor 1 (IGF1) axis and metabolic hormones have a central role for regulating hypertrophy of muscle fiber. We investigated age-related changes in GH-IGF1 axis-regulating factors and metabolic hormones in beef cattle. Ten Korean cattle steers were used. The longissimus thoracis (LT) samples were biopsied between the 11th and 12th rib at 12, 18, and 24 months of age. Steers were slaughtered at 34 month of age and the LT samples were collected. The LT samples were used for histological observation of muscle fiber size and detection of mRNA levels by real-time PCR analysis. Blood was collected at 12, 18, 24, and 34 months of age and used for hormone analyses. The mean muscle fiber size increased (P < 0.01) from 12 to 24 months, and remained unchanged at 34 months. Plasma GH concentrations were unchanged with age, whereas circulating IGF-1 concentrations decreased (P < 0.001) with age. Testosterone and insulin concentrations increased from 12 to 24 months and remained unchanged at 34 months. Leptin concentrations were unchanged from 12 to 24 months and increased at 34 months. The mRNA levels of growth hormone receptor (GHR) and signal transducer and activator of transcription 5a/b (STAT5a/b) decreased (P < 0.01) from 12 to 24 months, whereas mRNA levels of IGF-1 gene increased (P < 0.001) with age. Results indicate that the increased muscle fiber size in LT from 12 to 24 months are characterized with increasing concentrations of circulating testosterone and insulin. Age-dependent changes in muscle fiber hypertrophy were also related with changes in GHR, STAT5a/b, IGF-1 mRNA levels in the LT.

Function-specific calcium stores selectively regulate growth hormone secretion, storage, and mRNA level

2002 ◽  
Vol 282 (4) ◽  
pp. E810-E819 ◽  
Author(s):  
James D. Johnson ◽  
Christian Klausen ◽  
Hamid R. Habibi ◽  
John P. Chang
Keyword(s):  
Growth Hormone ◽  
Secretory Pathway ◽  
Mrna Level ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Signal Amplitude ◽  
Calcium Stores ◽  
Mrna Levels ◽  
Intracellular Ca

Ca+ stores may regulate multiple components of the secretory pathway. We examined the roles of biochemically independent intracellular Ca2+stores on acute and long-term growth hormone (GH) release, storage, and mRNA levels in goldfish somatotropes. Thapsigargin-evoked intracellular Ca2+ concentration ([Ca2+]i) signal amplitude was similar to the Ca2+-mobilizing agonist gonadotropin-releasing hormone, but thapsigargin (2 μM) did not acutely increase GH release, suggesting uncoupling between [Ca2+]i and exocytosis. However, 2 μM thapsigargin affected long-term secretory function. Thapsigargin-treated cells displayed a steady secretion of GH (2, 12, and 24 h), which decreased GH content (12 and 24 h), but not GH mRNA/production (24 h). In contrast to the results with thapsigargin, activating the ryanodine (Ry) receptor (RyR) with 1 nM Ry transiently increased GH release (2 h). Prolonged activation of RyR (24 h) reduced GH release, contents and apparent production, without changing GH mRNA levels. Inhibiting RyR with 10 μM Ry increased GH mRNA levels, production, and storage (2 h). Increasing [Ca2+]i independently of Ca2+stores with the use of 30 mM KCl decreased GH mRNA. Collectively, these results suggest that parts of the secretory pathway can be controlled independently by function-specific Ca2+ stores.

scholarly journals Sexually Dimorphic Growth Stimulation in a Strain of Growth Hormone Transgenic Coho Salmon (Oncorhynchus kisutch)

2021 ◽  
Author(s):  
Michelle T. T. Chan ◽  
Annette Muttray ◽  
Dionne Sakhrani ◽  
Krista Woodward ◽  
Jin-Hyoung Kim ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Growth Rate ◽  
Transgene Expression ◽  
Coho Salmon ◽  
Transgenic Fish ◽  
Growth Stimulation ◽  
Sexually Dimorphic ◽  
Mrna Levels ◽  
The Difference ◽  
Transgene Insertion

AbstractGrowth hormone (GH) transgenic fish often exhibit remarkable transformations in growth rate and other phenotypes relative to wild-type. The 5750A transgenic coho salmon strain exhibits strong sexually dimorphic growth, with females possessing growth stimulation at a level typical of that seen for both sexes in other strains harbouring the same gene construct (e.g. M77), while males display a modest level of growth stimulation. GH mRNA levels were significantly higher in females than in males of the 5750A strain but equivalent in the M77 strain, indicating sex and transgene insertion locus altered transgene expression. We found that acute estradiol treatments did not influence GH expression in either strain (5750A and M77) or the transgene promoter (metallothionein-B), suggesting that estradiol level was not a significant factor influencing transgene activity. The feminization of XX and XY fish of the 5750A and M77 strains generated all-female groups and resulted in equalized growth of the two genetic sexes, suggesting that the presence of the Y chromosome was not directly capable of influencing the GH transgene–mediated growth in a physiological female conditions. These data suggest that the difference in growth rate seen between the sexes in the 5750A strain arises from non-estradiol-mediated sex influences on gene regulation at the transgene locus. This study shows how genetic factors and transgene insertion sites can influence transgene expression with significant consequent effects on phenotype.

scholarly journals Beta-adrenergic stimulation of c-fos gene expression in the mouse submandibular gland.

1986 ◽  
Vol 6 (8) ◽  
pp. 2984-2989 ◽  
Author(s):  
T Barka ◽  
R M Gubits ◽  
H M van der Noen
Keyword(s):  
Mrna Level ◽  
Acinar Cells ◽  
Mrna Levels ◽  
Adrenergic Stimulation ◽  
Beta Adrenergic ◽  
Submandibular Glands ◽  
Fos Protein ◽  
Beta Adrenergic Agonist ◽  
Old Mice ◽  
Stimulation Of

Isoproterenol (IPR), a beta-adrenergic agonist, induces division of acinar cells in the parotid and submandibular glands of adult rodents and produces hyperplastic and hypertrophic enlargements of these organs. We analyzed the effects of IPR on thymidine incorporation, c-fos mRNA levels, and the immunocytochemical localization of c-fos protein in the submandibular glands of adult and of 5- and 14-day-old mice. In the glands of untreated mice c-fos transcripts were not detectable. In all experimental groups, administration of IPR led to a rapid, transient increase in the c-fos mRNA level. Propranolol blocked the IPR effect, while treatment with IPR and cycloheximide led to superinduction. We observed no correlation between the effect of IPR on cell replication or organ growth and stimulation of c-fos expression, and conclude that the latter is the result of beta-adrenergic receptor-IPR interaction. The c-fos protein was localized immunocytochemically in both the cytoplasm and the nuclei of acinar cells and in the nuclei of duct cells.

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