Document Detail

Glucose regulates ghrelin, neuropeptide Y, and the GH/IGF-I axis in the tilapia, Oreochromis mossambicus.
MedLine Citation:
PMID:  19735736     Owner:  NLM     Status:  MEDLINE    
In general, a fish's ability to clear glucose is sluggish in relation to mammals, which has lead to the idea that fish are glucose intolerant. It has been reported that circulating glucose levels do fluctuate in response to environmental challenges. Recent reports suggest that glucose may function as a metabolic signal regulating 'glucosensors' in the brain in fish, as has been reported in mammals. The current study was designed to investigate the effect of glucose on ghrelin and neuropeptide Y (NPY) signaling in the brain, and on the growth hormone/insulin-like growth factor-I (GH/IGF-I) in the tilapia, Oreochromis mossambicus. Glucose treatment significantly increased plasma and stomach mRNA levels of ghrelin. In the brain, mRNA levels of the ghrelin receptor (GRLN-R) were significantly reduced, whereas NPY mRNA levels were significantly elevated; suggesting that NPY containing neurons may be a "glucosensor" as reported in mammals. Glucose treatment resulted in changes in the GH/IGF-I axis. Liver mRNA levels of both GH receptors (GHR1 and GHR2) were significantly elevated, whereas liver IGF-I mRNA were unaltered by glucose treatment. No change in plasma or pituitary mRNA levels of GH was observed. Glucose significantly reduced plasma IGF-I levels. These data show that glucose regulates endocrine factors involved in appetite, growth, and possibly energy homeostasis, and suggests that glucose may be acting as a signal of metabolic status in fish.
Larry G Riley; Alicia P Walker; Casey P Dorough; Sara E Schwandt; E Gordon Grau
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2009-09-06
Journal Detail:
Title:  Comparative biochemistry and physiology. Part A, Molecular & integrative physiology     Volume:  154     ISSN:  1531-4332     ISO Abbreviation:  Comp. Biochem. Physiol., Part A Mol. Integr. Physiol.     Publication Date:  2009 Dec 
Date Detail:
Created Date:  2009-10-12     Completed Date:  2010-01-11     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9806096     Medline TA:  Comp Biochem Physiol A Mol Integr Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  541-6     Citation Subset:  IM    
California State University-Fresno, Department of Biology, Fresno, CA 93740, USA.
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MeSH Terms
Base Sequence
Blood Glucose / physiology*
DNA Primers
Ghrelin / blood,  genetics,  physiology*
Growth Hormone / blood,  physiology*
Insulin-Like Growth Factor I / physiology*
Liver / metabolism
Neuropeptide Y / blood,  genetics,  physiology*
Polymerase Chain Reaction
RNA, Messenger / genetics
Tilapia / physiology*
Reg. No./Substance:
0/Blood Glucose; 0/DNA Primers; 0/Ghrelin; 0/Neuropeptide Y; 0/RNA, Messenger; 67763-96-6/Insulin-Like Growth Factor I; 9002-72-6/Growth Hormone

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