Acute Exercise Suppresses Hypothalamic PTP1B Protein Level and Improves Insulin and Leptin Signaling in Obese Rats
AJP Endocrinology and Metabolism
Published online on July 23, 2013
Abstract
Hypothalamic inflammation is associated with insulin and leptin resistance, hyperphagia and obesity. In this scenario, hypothalamic protein tyrosine phosphatase 1B (PTP1B) has emerged as the key phosphatase induced by inflammation responsible for the central insulin and leptin resistance. Here, we demonstrated that acute exercise reduced inflammation and PTP1B protein level/activity in the hypothalamus of obese rodents. Exercise disrupted the interaction between PTP1B with proteins involved in the early steps of insulin (IRβ and IRS1) and leptin (Jak2) signaling, increased the tyrosine phosphorylation of these molecules and restored the anorexigenic effects of insulin and leptin in obese rats. Interestingly, the anti-inflammatory action and the reduction of PTP1B activity mediated by exercise occurred in an Interleukin-6 (IL-6)-dependent manner, because exercise failed to reduce inflammation and PTP1B protein level after the disruption of hypothalamic-specific IL-6 action in obese rats. Conversely, intracerebroventricular (ICV) administration of recombinant IL-6 reproduced the effects of exercise, improving hypothalamic insulin and leptin action by reducing the inflammatory signaling and PTP1B activity in obese rats at rest. Taken together, our study reports that physical exercise restores insulin and leptin signaling, at least in part, by reducing hypothalamic PTP1B protein level through the central anti-inflammatory response.