Brown adipose tissue: the dominant site of nonshivering thermogenesis in the rat

Measurements with tracer microspheres of changes in tissue blood flow associated with noradrenaline (NA)-induced calorigenesis in warm-acclimated and in cold-acclimated (CA) rats revealed very large increases in flow to brown adipose tissue (BAT). The data on flow together with measurements of the arteriovenous difference in blood O2 across interscapular BAT indicate that BAT accounts for at least 60% of the NA-induced nonshivering thermogenesis (NST) of CA rats. Skeletal muscle was found to be only minimally, if at all, involved in this NST.