Initial Stages of the Insulin Signaling System in the Brain of Rats with Experimental Diabetes Mellitus

We studied reactivity of insulin signal pathway elements, insulin receptor and insulin receptor substrate protein-2 (IRS2 protein), in rat brain in response to insulin insufficiency and insulin resistance during the development of experimental type 1 or type 2 diabetes mellitus. In type 1 diabetes mellitus characterized by acute insulin insufficiency, specific binding of insulin in rat brain increased 2-fold in comparison with the control and IRS2-gene expression in rat hypothalamus and cortex 2-4 fold surpassed the normal values. In type 2 diabetes mellitus (110 and 190 days of development), changes in the test parameters in rat brain were less pronounced. These findings attest to involvement of the brain insulin signal pathway into the response to systemic insulin deficiency in type 1 diabetes mellitus.