Hui Dong1, Jian-hong Wang, Fu-er Lu, Li-jun Xu, Yan-lin Gong, Xin Zou. 1. Institute of Integrative Traditional Chinese and Western Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Abstract
OBJECTIVE: To investigate the effect of Jiaotai Pill (, JTP) at different constitutional proportions on insulin signaling through phosphatidylinositol 3-kinase (PI3K) pathway in the skeletal muscle of diabetic rats. METHODS: The rat model of type 2 diabetes mellitus (T2DM) was established by intravenous injection of a small dose of streptozotoein plus high fat diet feeding. JTP at the same dosage of cinnamon and the increasing dosage of Coptis chinensis was administered to diabetic rats for nine weeks respectively. Plasma glucose and insulin levels were assayed. The expressions of proteins were determined by Western blot method. RESULTS: All the three formulations of JTP decreased plasma glucose and fasting insulin levels as well as increased the protein expressions of insulin receptor β (InsRβ) subunit, insulin receptor substrate-1 (IRS-1), PI3K p85 subunit and glucose transporter 4 (GLUT4) in skeletal muscle. Meanwhile, JTP increased the tyrosine phosphorylation of InsRβ subunit and IRS-1, and reduced the serine phosphorylation of IRS-1 in skeletal muscle. Interestingly, the effect of JTP on improving insulin sensitivity was not dose-dependent. In contrast, JTP containing the least amount of Coptis chinensis exhibited the best effect. CONCLUSION: JTP at different constitutional proportions attenuates the development of diabetes in a rat model of T2DM. The mechanism might be associated with enhancing insulin signaling through PI3K pathway in the skeletal muscle.
OBJECTIVE: To investigate the effect of Jiaotai Pill (, JTP) at different constitutional proportions on insulin signaling through phosphatidylinositol 3-kinase (PI3K) pathway in the skeletal muscle of diabeticrats. METHODS: The rat model of type 2 diabetes mellitus (T2DM) was established by intravenous injection of a small dose of streptozotoein plus high fat diet feeding. JTP at the same dosage of cinnamon and the increasing dosage of Coptis chinensis was administered to diabeticrats for nine weeks respectively. Plasma glucose and insulin levels were assayed. The expressions of proteins were determined by Western blot method. RESULTS: All the three formulations of JTP decreased plasma glucose and fasting insulin levels as well as increased the protein expressions of insulin receptor β (InsRβ) subunit, insulin receptor substrate-1 (IRS-1), PI3K p85 subunit and glucose transporter 4 (GLUT4) in skeletal muscle. Meanwhile, JTP increased the tyrosine phosphorylation of InsRβ subunit and IRS-1, and reduced the serine phosphorylation of IRS-1 in skeletal muscle. Interestingly, the effect of JTP on improving insulin sensitivity was not dose-dependent. In contrast, JTP containing the least amount of Coptis chinensis exhibited the best effect. CONCLUSION: JTP at different constitutional proportions attenuates the development of diabetes in a rat model of T2DM. The mechanism might be associated with enhancing insulin signaling through PI3K pathway in the skeletal muscle.
Authors: Juliana C N Chan; Vasanti Malik; Weiping Jia; Takashi Kadowaki; Chittaranjan S Yajnik; Kun-Ho Yoon; Frank B Hu Journal: JAMA Date: 2009-05-27 Impact factor: 56.272