The effects of glucagon-like peptide-1 (GLP-1) on adipose cells in type-2 diabetes mellitus (T2DM) / Noor Mazuin Abu Bakar

Glucagon-like peptide 1 (GLP-1) is a member of incretin group hormone. It is produced by the L-cells of the intestines, serving as a postprandial communication messenger between the gut and other organs. It has numerous physiological roles, such as improving glucose-stimulated insulin secretion, enhancement of pancreatic β-cell proliferation, inhibition of glucagon release and promotion of satiety. GLP-1 has attracted an immense interest in research due to its antidiabetic effects for the treatment of patients with Type-2 Diabetes Mellitus (T2DM). However, the direct effects of GLP-1 on adipocytes are poorly characterized. In this study, an in vitro model of a dexamethasone-induced T2DM 3T3-L1 mouse adipose cells was chosen to demonstrate the metabolic effects of GLP-1 treatment and its actions on the cell’s gene expression. Four parameters were measured to observe the changes in the cells; (i) glucose uptake, (ii) glycerol release in cellular adipolysis, (iii) glycogen synthesis, and (iv) gene expressions of adipokines and glucose transporters through real-time PCR. Results showed that successful adipocyte differentiation was obtained from the methylisobutylxanthine, dexamethasone and insulin (MDI) mix resulted in the presence of lipid droplets as observed with oil red O staining. GLP-1 has stimulated the glucose uptake by 3T3-L1 adipocyte cells and its utilization for lipid synthesis was enhanced. It also appears that GLP-1 preferentially inhibited lipid degradation and encouraged glycogen synthesis. From the findings, GLP-1 has demonstrated ameliorative effects on the metabolic process that involves glucose and lipid in the cells, as well as on the secretion of adipokines and glucose transporters by the 3T3-L1 cells. Thus, GLP-1 may have a potential role as an antidiabetic therapy in the treatment of T2DM.