[HTML][HTML] Central insulin action regulates peripheral glucose and fat metabolism in mice

L Koch, FT Wunderlich, J Seibler… - The Journal of …, 2008 - Am Soc Clin Investig
L Koch, FT Wunderlich, J Seibler, AC Könner, B Hampel, S Irlenbusch, G Brabant, CR Kahn
The Journal of clinical investigation, 2008Am Soc Clin Investig
Insulin resistance is a hallmark of type 2 diabetes, and many insights into the functions of
insulin have been gained through the study of mice lacking the IR. To gain a better
understanding of the role of insulin action in the brain versus peripheral tissues, we created
2 mouse models with inducible IR inactivation, 1 in all tissues including brain (IRΔwb), and 1
restricted to peripheral tissues (IRΔper). While downregulation of IR expression resulted in
severe hyperinsulinemia in both models, hyperglycemia was more pronounced in IRΔwb …
Insulin resistance is a hallmark of type 2 diabetes, and many insights into the functions of insulin have been gained through the study of mice lacking the IR. To gain a better understanding of the role of insulin action in the brain versus peripheral tissues, we created 2 mouse models with inducible IR inactivation, 1 in all tissues including brain (IRΔwb), and 1 restricted to peripheral tissues (IRΔper). While downregulation of IR expression resulted in severe hyperinsulinemia in both models, hyperglycemia was more pronounced in IRΔwb mice. Both strains displayed a dramatic upregulation of hepatic leptin receptor expression, while only IRΔper mice displayed increased hepatic Stat3 phosphorylation and Il6 expression. Despite a similar reduction in IR expression in white adipose tissue (WAT) mass in both models, IRΔwb mice had a more pronounced reduction in WAT mass and severe hypoleptinemia. Leptin replacement restored hepatic Stat3 phosphorylation and normalized glucose metabolism in these mice, indicating that alterations in glucose metabolism occur largely as a consequence of lipoathrophy upon body-wide IR deletion. Moreover, chronic intracerebroventricular insulin treatment of control mice increased fat mass, fat cell size, and adipose tissue lipoprotein lipase expression, indicating that CNS insulin action promotes lipogenesis. These studies demonstrate that central insulin action plays an important role in regulating WAT mass and glucose metabolism via hepatic Stat3 activation.
The Journal of Clinical Investigation