Insulin at the Intersection of Thermoregulation and Glucose Homeostasis.

Energy expenditure and insulin-mediated glucose fluxes are reduced in thermoneutral (TN)-adapted mice versus room 'laboratory' temperature (RT)-adapted mice.Reduced insulin sensitivity manifests in TN mice regardless of whether they are TN-adapted or short-term transitioned from RT-adapted to TN.TN-adapted mice are resistant to the RT-induced increase in whole-body insulin sensitivity even though metabolic rate is increased.TN-adapted mice switched to RT meets increased thermogenic needs, not by increasing glucose uptake, but by partitioning a greater fraction of glucose from glycogen storage to glycolysis.Brown fat glucose uptake sensitively increases with RT and decreases with TN by an insulin-independent mechanism.