Background: Glucose-dependent insulinotropic polypeptide (GIP) is a gastrointestinal hormone that is secreted in response to food intake. GIP acts on various tissues, including pancreatic ß-cells, via interaction with its G-protein-coupled receptor. Some studies in rodents suggested that GIP directly links overnutrition to obesity. GIP exerts a physiological role on lipid uptake into adipocytes.
Objectives: To analyse the effect of GIP-Infusions on changes in adipose tissue gene expression at different blood-glucose levels in obese men and also detect different biomarkers and hormone interactions caused by GIP.
Setting and participants: Seventeen healthy overweight men (BMI: 2840 kg/m2; age: 3065 years) with normal glucose tolerance underwent a single-blind intervention study at four different time points with euglycaemic or hyperglycaemic clamps in combination with GIP or saline infusions. Each solution was applied at physiological concentrations for 4 h. Before and after the infusions biopsies from subcutaneous adipose tissue were taken. We isolated total RNA from all fat biopsies and hybridized the RNA to Agilent Whole Human Genome Microarrays. The results were verified by RT-PCR.
Results: Using Agilent Genespring Software and the MetaCore platform we identified several genes being involved in inflammatory processes. Under euglycaemic hyperinsulinaemic clamp conditions in combinations with a GIP-Infusion we find a significant upregulation of chemokine ligand 2 (CCL-2/MCP-1), interleukin-1ß (IL-1ß) and interleukin-6.
Conclusion: GIP may play a role in inflammatory processes in adipose tissue of obese men.
25 - 29 Apr 2009
European Society of Endocrinology