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Insulin modulates glucose-dependent insulinotropic polypeptide (GIP) secretion from enteroendocrine K cells in rats

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Irwin, Nigel, Francis, Jacqueline M. E. and Flatt, Peter (2011) Insulin modulates glucose-dependent insulinotropic polypeptide (GIP) secretion from enteroendocrine K cells in rats. BIOLOGICAL CHEMISTRY, 392 (10). pp. 909-918. [Journal article]

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DOI: 10.1515/BC.2011.176

Abstract

Effects of insulin excess and deficiency on glucose-dependent insulinotropic polypeptide (GIP) was examined in rats following insulinoma transplantation or streptozotocin (STZ) administration. Over 14 days, food intake was increased (p<0.001) in both groups of rats, with decreased body weight (p<0.01) in STZ rats. Non-fasting plasma glucose levels were decreased (p<0.01) and plasma insulin levels increased (p<0.001) in insulinoma-bearing rats, whereas STZ treatment elevated glucose (p<0.001) and decreased insulin (p<0.01). Circulating GIP concentrations were elevated (p<0.01) in both animal models. At 14 days, oral glucose resulted in a decreased glycaemic excursion (p<0.05) with concomitant elevations in insulin release (p<0.001) in insulinoma-bearing rats, whereas STZ-treated rats displayed similar glucose-lowering effects but reduced insulin levels (p<0.01). GIP concentrations were augmented in STZ rats (p<0.05) following oral glucose. Plasma glucose and insulin concentrations were not affected by oral fat, but fat-induced GIP secretion was particularly (p<0.05) increased in insulinoma-bearing rats. Exogenous GIP enhanced (p<0.05) glucose-lowering in all groups of rats accompanied by insulin releasing (p<0.001) effects in insulinoma-bearing and control rats. Both rat models exhibited increased (p<0.001) intestinal weight but decreased intestinal GIP concentrations. These data suggest that circulating insulin has direct and indirect effects on the synthesis and secretion of GIP.

Item Type:Journal article
Faculties and Schools:Faculty of Life and Health Sciences
Faculty of Life and Health Sciences > School of Biomedical Sciences
Faculty of Life and Health Sciences > School of Pharmacy and Pharmaceutical Science
Research Institutes and Groups:Biomedical Sciences Research Institute
Biomedical Sciences Research Institute > Diabetes
ID Code:20371
Deposited By:Dr Nigel Irwin
Deposited On:28 Oct 2011 12:16
Last Modified:19 Nov 2012 15:37

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