Insulin treatment affects brain protein synthesis rate in streptozotocin-induced diabetic rats

The purpose of this study was to determine whether insulin treatment affected the rate of brain protein synthesis in diabetic rats. Experiments were conducted on three groups of rats given streptozotocin without insulin treatment (diabetes), treated with streptozotocin + insulin (diabetes + insulin) or treated with neither streptozotocin nor insulin (control). The fractional rates of protein synthesis in brain, liver and kidney of diabetic rats treated with insulin were significantly greater than in diabetic rats without insulin treatment. In brain, liver and kidney, the RNA activity [g protein synthesized/(g RNA.d)] was significantly correlated with the fractional rate of protein synthesis. The RNA concentration (mg RNA/g protein) was not related to the fractional rate of protein synthesis in any organ. The results suggest that insulin treatment of diabetic rats is likely to increase the rate of protein synthesis in the brain, and that RNA activity is related to the fractional rate of brain protein synthesis.