Hexane Extract of Induces Insulin Expression and Prevents Glucotoxicity in INS-1 Cells

• Main Authors: Hae-Jung Lee, Yoon-Jung Choi, So-Young Park, Jong-Yeon Kim, Kyu-Chang Won, Jong-Keun Son, Yong-Woon Kim
• Format: Article
• Language: English
• Published: Korean Diabetes Association 2015-02-01
• Series: Diabetes & Metabolism Journal
• Subjects: Glucose-stimulated insulin secretion, Insulin mRNA; Glucotoxicity
• Online Access: http://e-dmj.org/Synapse/Data/PDFData/2004DMJ/dmj-39-51.pdf

BackgroundHyperglycemia, a characteristic feature of diabetes, induces glucotoxicity in pancreatic β-cells, resulting in further impairment of insulin secretion and worsening glycemic control. Thus, preservation of insulin secretory capacity is essential for the management of type 2 diabetes. In this study, we evaluated the ability of an Orthosiphon stamineus (OS) extract to prevent glucotoxicity in insulin-producing cells.MethodsWe measured insulin mRNA expression and glucose-stimulated insulin secretion (GSIS) in OS-treated INS-1 cells after exposure to a high glucose (HG; 30 mM) concentration.ResultsThe hexane extract of OS elevated mRNA expression of insulin as well as pancreatic and duodenal homeobox-1 of INS-1 cells in a dose-dependent manner. The hexane OS extract also increased the levels of phosphorylated phosphatidylinositol 3-kinase (PI3K) in a concentration-dependent manner. Additionally, Akt phosphorylation was elevated by treatment with 100 and 200 µmol of the hexane OS extract. Three days of HG exposure suppressed insulin mRNA expression and GSIS; these expressions were restored by treatment with the hexane OS extract. HG elevated peroxide levels in the INS-1 cells. These levels were unaffected by OS treatment under both normal and hyperglycemic conditions.ConclusionOur results suggested that the hexane extract of OS elevates insulin mRNA expression and prevents glucotoxicity induced by a 3-day treatment with HG. This was associated with the activation of PI-3K and Akt.