[#2012-06] Reishi Teng, B.S. Hypoglycemic effect and mechanism of a proteoglyca

Abstract. – Background and Objectives: Diabetes mellitus inducing a leading cause of morbidity are widespread in the entire globe. The present study was to investigate the antidiabetic potency and mechanism of a proteoglycan extract, named FYGL (Fudan-Yueyang-G. lucidum), from the fruiting bodies of Ganoderma Lucidum as published recently, using streptozotocin-
induced type 2 diabetic mellitus (T2DM) rats. Material and Methods: The T2DM model rats were treated with FYGL as well as metformin and rosiglitazone. The levels of plasma glucose and insulin were measured, and the expression and activity of the protein tyrosine phosphatase 1B (PTP1B) and the tyrosine phosphorylation level of the insulin receptor (IR) β-subunit in the
livers and skeletal muscles of the T2DM rats were analyzed by immunoprecipitation and Western blotting methods. In addition, the levels of free fatty acid and serum lipid profile were measured using commercial kits for those trailed rats. Results: The decrease in fasting plasma glucose and the increase in insulin concentration dose- and time-dependently in the T2DM rats
treated by FYGL, comparable with that by the clinical drugs, metformin and rosiglitazone. The levels of the PTP1B expression and activity were decreased, and the tyrosine phosphorylation level of the IR β-subunit was increased in the skeletal muscles of the T2DM rats. Furthermore, FYGL significantly decreased the levels of free fatty acid, triglyceride, total cholesterol and low density lipoprotein-cholesterol as well as increased the level of high density lipoproteincholesterol.