Insulin action in AgRP-expressing neurons is required for suppression of hepatic glucose production.
Könner AC., Janoschek R., Plum L., Jordan SD., Rother E., Ma X., Xu C., Enriori P., Hampel B., Barsh GS., Kahn CR., Cowley MA., Ashcroft FM., Brüning JC.
Insulin action in the central nervous system regulates energy homeostasis and glucose metabolism. To define the insulin-responsive neurons that mediate these effects, we generated mice with selective inactivation of the insulin receptor (IR) in either pro-opiomelanocortin (POMC)- or agouti-related peptide (AgRP)-expressing neurons of the arcuate nucleus of the hypothalamus. While neither POMC- nor AgRP-restricted IR knockout mice exhibited altered energy homeostasis, insulin failed to normally suppress hepatic glucose production during euglycemic-hyperinsulinemic clamps in AgRP-IR knockout (IR(DeltaAgRP)) mice. These mice also exhibited reduced insulin-stimulated hepatic interleukin-6 expression and increased hepatic expression of glucose-6-phosphatase. These results directly demonstrate that insulin action in POMC and AgRP cells is not required for steady-state regulation of food intake and body weight. However, insulin action specifically in AgRP-expressing neurons does play a critical role in controlling hepatic glucose production and may provide a target for the treatment of insulin resistance in type 2 diabetes.