Effects of growth hormone, insulin-like growth factor I, triiodothyronine, thyroxine, and cortisol on gene expression of carbohydrate metabolic enzymes in sea bream hepatocytes

Leung, Ling Yan; Woo, Norman Y.S.

doi:10.1016/j.cbpa.2010.07.010

Cited by 22 publications

(15 citation statements)

References 76 publications

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“…Reduced GP activity was also found in trout deprived of food for 30 d (Vijayan and Moon 1992); this study suggests that this effect is implemented relatively rapidly, that is, within 5 d. Hepatic GP activities were also similar between cortisol-treated and subordinate fish. Data on the effects of cortisol elevation on GP activity are sparse but generally suggest little effect (Soengas et al 1992;Mommsen et al 1999;LaizCarrion et al 2003;Leung and Woo 2010). However, lowered GP activity in cortisol-treated fish is consistent with the role of cortisol in promoting restoration of glycogen reserves depleted during acute stress .…”

Section: Discussionmentioning

confidence: 67%

“…Fasted fish did not exhibit elevated hepatic PEPCK activity (DiBattista et al 2006), and glucose production by hepatocytes from fasted fish was low, as in previous studies (Van Heeswijk et al 2006), and did not exceed glycogen use. The enhanced gluconeogenic capacity of subordinate fish likely reflects the influence of cortisol, which has been found to increase the activities of the key gluconeogenic enzymes, including glucose 6-phosphatase, fructose 1,6-bisphosphatase, and PEPCK (e.g., Chan and Woo 1978;Foster and Moon 1986;Vijayan et al 1991Vijayan et al , 2003Leung and Woo 2010; see also review by Mommsen et al 1999). Correspondingly, administration of RU-486 eliminated differences in hepatic PEPCK activity between dominant and subordinate trout (DiBattista et al 2006).…”

Section: Discussionmentioning

confidence: 97%

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The Influence of Social Status on Hepatic Glucose Metabolism in Rainbow TroutOncorhynchus mykiss

Gilmour

Kirkpatrick

Massarsky

et al. 2012

Physiological and Biochemical Zoology

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The effects of chronic social stress on hepatic glycogen metabolism were examined in rainbow trout Oncorhynchus mykiss by comparing hepatocyte glucose production, liver glycogen phosphorylase (GP) activity, and liver β-adrenergic receptors in dominant, subordinate, control, fasted, and cortisol-treated fish. Hepatocyte glucose production in subordinate fish was approximately half that of dominant fish, reflecting hepatocyte glycogen stores in subordinate trout that were just 16% of those in dominant fish. Fasting and/or chronic elevation of cortisol likely contributed to these differences based on similarities among subordinate, fasted, and cortisol-treated fish. However, calculation of the "glycogen gap"--the difference between glycogen stores used and glucose produced--suggested an enhanced gluconeogenic potential in subordinate fish that was not present in fasted or cortisol-treated trout. Subordinate, fasted, and cortisol-treated trout also exhibited similar GP activities (both total activity and that of the active or a form), and these activities were in all cases significantly lower than those in control trout, perhaps reflecting an attempt to protect liver glycogen stores or a modified capacity to activate GP. Dominant trout exhibited the lowest GP activities (20%-24% of the values in control trout). Low GP activities, presumably in conjunction with incoming energy from feeding, allowed dominant fish to achieve the highest liver glycogen concentrations (double the value in control trout). Liver membrane β-adrenoceptor numbers (assessed as the number of (3)H-CGP binding sites) were significantly lower in subordinate than in dominant trout, although this difference did not translate into attenuated adrenergic responsiveness in hepatocyte glucose production in vitro. Transcriptional regulation, likely as a result of fasting, was indicated by significantly lower β(2)-adrenoceptor relative mRNA levels in subordinate and fasted trout. Collectively, the data indicate that social status shapes liver metabolism and in particular glycogen metabolism, favoring accumulation of glycogen reserves from incoming energy in dominant fish and reliance on onboard fuels in subordinate fish.

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Section: Discussionmentioning

confidence: 67%

Section: Discussionmentioning

confidence: 97%

The Influence of Social Status on Hepatic Glucose Metabolism in Rainbow TroutOncorhynchus mykiss

Gilmour

Kirkpatrick

Massarsky

et al. 2012

Physiological and Biochemical Zoology

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“…The often assumed inability of fish to utilize carbohydrate (glucose) as energy source has been attributed to the absence of an inducible GK (Wilson 1994); however, the existence of a GK gene was reported in the liver of silver sea bream (Leung and Woo 2010), gilthead sea bream (Caseras et al 2002;Panserat et al 2000a), carp and rainbow trout (Panserat et al 2000a), implying that fish are potentially able to metabolize carbohydrates. In the present study, fish fed 20% dextrin had a 28-fold increase in GK mRNA level over fish fed 2% dextrin, indicating that in silver sea bream, GK was highly inducible by dietary carbohydrate.…”

Section: Expression Of Hepatic Carbohydrate Metabolic Enzymesmentioning

confidence: 96%

“…EU590130), GP (GenBank accession no. EU525932) (Leung and Woo 2010), G6PDH (GenBank accession no. AY754640), GH (GenBank accession no.…”

Section: Standard Preparation and Real-time Pcrmentioning

confidence: 99%

“…Recently, genes coding for key enzymes in different carbohydrate metabolic pathways have been cloned and characterized in various fish tissues (Blin et al 1999;Deane and Woo 2005;Metón et al 2004;Panserat et al 2000aPanserat et al , c, 2002Leung and Woo 2010), and regulation of these enzymes at the molecular level by dietary carbohydrate manipulation has been reported (Panserat et al 2001(Panserat et al , 2002. These studies, however, have mostly been centered on glycolysis and gluconeogenesis, and to date, a complete study on the molecular regulation of all pathways of carbohydrate metabolism has not been attempted for any fish species.…”

Section: Introductionmentioning

confidence: 96%

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Influence of dietary carbohydrate level on endocrine status and hepatic carbohydrate metabolism in the marine fish Sparus sarba

Leung

Woo

2011

Fish Physiol Biochem

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Silver sea bream, Sparus sarba, were fed two diets of different carbohydrate levels (2 and 20% dextrin) for 4 weeks, and the effects on organ indices, liver composition, serum metabolite and hormone levels and gene expression profile of key enzymes of carbohydrate metabolism in the liver were investigated. By using real-time PCR, mRNA expression levels of carbohydrate metabolic enzymes including glucokinase (GK, glycolysis), glucose-6-phosphatase (G6Pase, gluconeogenesis), glycogen synthase (GS, glycogenesis), glycogen phosphorylase (GP, glycogenolysis) and glucose-6-phosphate dehydrogenase (G6PDH, pentose phosphate pathway) in liver of sea bream have been examined, and it was found that high dietary carbohydrate level increased mRNA level of GK but decreased mRNA levels of G6Pase and GP. However, mRNA levels of GS and G6PDH were not significantly influenced by dietary carbohydrate. Silver sea bream fed high dietary carbohydrate had higher hepatosomatic index (HSI), liver glycogen and protein, but there were no significant changes in gonadosomatic index (GSI), serum glucose and protein level, as well as liver lipid and moisture level. Pituitary growth hormone (GH) and hepatic insulin-like growth factor I (IGF-I) transcript abundance were assayed by real-time PCR, and it was found that both parameters remained unchanged in fish fed different dietary carbohydrate levels. Serum triiodothyronine (T(3)) and thyroxine (T(4)) were not significantly affected by dietary carbohydrate levels, but lower serum cortisol level was found in fish fed high dietary carbohydrate level. These results suggest that silver sea bream is able to adapt to a diet with high carbohydrate content (up to 20% dextrin), the consumption of which would lead to fundamental re-organization of carbohydrate metabolism resulting in hepatic glycogen deposition.

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Carbohydrates

Hemre¹,

Deng²

2015

Dietary Nutrients, Additives, and Fish Health

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Effects of growth hormone, insulin-like growth factor I, triiodothyronine, thyroxine, and cortisol on gene expression of carbohydrate metabolic enzymes in sea bream hepatocytes

Cited by 22 publications

References 76 publications

The Influence of Social Status on Hepatic Glucose Metabolism in Rainbow TroutOncorhynchus mykiss

The Influence of Social Status on Hepatic Glucose Metabolism in Rainbow TroutOncorhynchus mykiss

Influence of dietary carbohydrate level on endocrine status and hepatic carbohydrate metabolism in the marine fish Sparus sarba

Carbohydrates

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