Antihyperglycemic action of isoferulic acid in streptozotocin-induced diabetic rats

1 Wistar rats with streptozotocin-induced diabetes (STZ-diabetic rats), whi ch is similar to human insulin-dependent diabetic mellitus (IDDM), were emp loyed to investigate the antihyperglycemic action of isoferulic acid. 2 A single intravenous injection of isoferulic acid decreased the plasma gl ucose in a dose-dependent manner in the STZ-diabetic rats. Repeated intrave nous administration of STZ-diabetic rats with isoferulic acid (5.0 mg kg(-1 )) also resulted in the lowering of plasma glucose after one day. 3 Stimulatory effects of isoferulic acid on the glucose uptake and glycogen synthesis in soleus muscles isolated from STZ-diabetic rats were also obta ined indicating an increase of glucose utilization following isoferulic aci d treatment which was not dependent on insulin. 4 The mRNA level of glucose transporter subtype 4 form (GLUT4) in soleus mu scle was raised by isoferulic acid after repeated treatment for 1 day in ST Z-diabetic rats. Similar repeated treatment with isoferulic acid reversed t he elevated mRNA level of phosphoenolpyruvate carboxykinase (PEPCK) in live r of STZ-diabetic rats to the normal level. However, expression of GLUT4 an d PEPCK genes in nondiabetic rats were not influenced by similar treatment with isoferulic acid. 5 These results suggest that isoferulic acid can inhibit hepatic gluconeoge nesis and/or increase the glucose utilization in peripheral tissue to lower plasma glucose in diabetic rats lacking insulin.