Document Detail


In vivo and in vitro suppression by leptin of glucose-stimulated insulin hypersecretion in high glucose-fed rats.
MedLine Citation:
PMID:  11022188     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVES: Chronic feeding to rats of high glycaemic index (GI) diets results in the hypersecretion of insulin in response to an i.v. glucose load. The first aim of this study was to see if this exaggerated insulin response was accompanied by a hypersensitivity to glucose stimulation in isolated islets in vitro. The second aim was to see if the adipocyte factor, leptin, was able to alter insulin secretion in this model both in vivo and in vitro. DESIGN AND METHODS: Rats were fed for 6 weeks either a high GI diet in which the carbohydrate component was mostly glucose (GLUC diet) or a low GI diet containing mostly amylose (AMOSE diet). Rats then underwent an i.v. glucose tolerance test (ivGTT) (1g/kg) with and without a prior infusion of leptin (133 microg/kg perh). Islets were then isolated from these rats and basal and glucose-stimulated insulin secretion (GSIS) measured in both the absence and presence (100ng/ml) of leptin. RESULTS AND CONCLUSIONS: Peak insulin response during the ivGTT was 3-fold greater in GLUC rats (P<0.001). Leptin had no effect on AMOSE rat insulin response but lowered the GLUC rat response to AMOSE rat levels. In vitro, basal insulin secretion was 4-fold greater in GLUC rats (P<0.05). At 20mmol/l glucose, there was no further increase in insulin secretion in GLUC rats but a 2-fold increase in AMOSE rats. Leptin had no effect on basal insulin secretion or GSIS in AMOSE rats but reduced basal insulin secretion and GSIS in GLUC rats. These results show insulin hypersecretion in high GI-fed rats may be reduced by leptin.
Authors:
G Widdup; J M Bryson; D Pawlak; J L Phuyal; G S Denyer; I D Caterson
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  European journal of endocrinology / European Federation of Endocrine Societies     Volume:  143     ISSN:  0804-4643     ISO Abbreviation:  Eur. J. Endocrinol.     Publication Date:  2000 Sep 
Date Detail:
Created Date:  2000-10-26     Completed Date:  2000-10-26     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9423848     Medline TA:  Eur J Endocrinol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  431-7     Citation Subset:  IM    
Affiliation:
Human Nutrition Unit, Department of Biochemistry, University of Sydney, Sydney, New South Wales 2006, Australia.
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MeSH Terms
Descriptor/Qualifier:
Animals
Area Under Curve
Body Weight / drug effects
Diet
Glucose / administration & dosage*,  antagonists & inhibitors*
Glucose Tolerance Test
Insulin / blood,  secretion*
Islets of Langerhans / drug effects,  metabolism
Leptin / blood,  pharmacology*
Male
Rats
Rats, Wistar
Chemical
Reg. No./Substance:
0/Leptin; 11061-68-0/Insulin; 50-99-7/Glucose

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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