| The role of hepatic, renal and intestinal gluconeogenic enzymes in glucose homeostasis of juvenile rainbow trout. | |
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MedLine Citation:
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PMID: 18180932 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Rainbow trout is unable to utilize high levels of dietary carbohydrates and experiences hyperglycemia after consumption of carbohydrate-rich meals. Carbohydrates stimulate hepatic glycolytic activity, but gene expression of the rate-limiting gluconeogenic enzymes glucose-6-phosphatase (G6Pase), fructose-1,6-bisphosphatase (FBPase) and phosphoenolpyruvate carboxykinase (PEPCK) remains high. Although there is significant mRNA expression and activity of gluconeogenic enzymes in trout intestine and kidney, the regulation of these enzymes by diet is not known. We tested the hypothesis that dietary carbohydrate modulates intestinal and renal G6Pase, FBPase and PEPCK. Fish were either fasted or fed isocaloric carbohydrate-free (CF) or high carbohydrate (HC) diets for 14 days. As expected, fish fed HC exhibited postprandial hyperglycemia and enhanced levels of hepatic glucokinase mRNA and activity. Dietary carbohydrates had no significant effect on the expression and activity of PEPCK, FBPase and G6Pase in all three organs. In contrast, fasting enhanced the activity, but not the mRNA expression of both hepatic and intestinal PEPCK, as well as intestinal FBPase. Therefore, the activity of rate-limiting gluconeogenic enzymes in trout can be modified by fasting, but not by the carbohydrate content of the diet, potentially causing hyperglycemia when fed high levels of dietary carbohydrates. In this species consuming low carbohydrate diets at infrequent intervals in the wild, fasting-induced increases in hepatic and intestinal gluconeogenic enzyme activities may be a key adaptation to prevent perturbations in blood glucose during food deprivation. |
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Authors:
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Séverine Kirchner; Stéphane Panserat; Pauline L Lim; Sadasivam Kaushik; Ronaldo P Ferraris |
Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, Non-P.H.S. Date: 2008-01-08 |
Journal Detail:
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Title: Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology Volume: 178 ISSN: 0174-1578 ISO Abbreviation: J. Comp. Physiol. B, Biochem. Syst. Environ. Physiol. Publication Date: 2008 Mar |
Date Detail:
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Created Date: 2008-02-22 Completed Date: 2008-07-03 Revised Date: 2009-06-08 |
Medline Journal Info:
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Nlm Unique ID: 8413200 Medline TA: J Comp Physiol B Country: Germany |
Other Details:
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Languages: eng Pagination: 429-38 Citation Subset: IM |
Affiliation:
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Department of Pharmacology and Physiology, University of Medicine and Dentistry of New Jersey (UMDNJ), New Jersey Medical School, Newark, 07103-2714, USA. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Dietary Carbohydrates / pharmacology Fructose-Bisphosphatase / metabolism Gluconeogenesis / physiology* Glucose / metabolism* Glucose-6-Phosphatase / metabolism Homeostasis / physiology* Intestines / enzymology* Kidney / enzymology* Liver / enzymology* Oncorhynchus mykiss / metabolism* Phosphoenolpyruvate Carboxykinase (ATP) / metabolism RNA, Messenger / metabolism |
| Chemical | |
Reg. No./Substance:
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0/Dietary Carbohydrates; 0/RNA, Messenger; 50-99-7/Glucose; EC 3.1.3.11/Fructose-Bisphosphatase; EC 3.1.3.9/Glucose-6-Phosphatase; EC 4.1.1.49/Phosphoenolpyruvate Carboxykinase (ATP) |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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