Sympathetic denervation impairs responses of brown adipose tissue to VMH stimulation

Effects of unilateral surgical denervation of the interscapular brown adipose tissue (IBAT) on its thermogenic and lipogenic responses to electrical stimulation of the ventromedial hypothalamic (VMH) nucleus were studied in anesthetized rats. The rapid rise in IBAT temperature in response to VMH stimulation was greatly suppressed in the denervated IBAT, whereas the temperature response was not impaired in the contralateral innervated IBAT in the same animals. Similarly, the increased rates of conversion of [14C] glucose and [3H]H2O to fatty acids and glyceride glycerol in vivo in IBAT after VMH stimulation were almost completely inhibited by sympathetic denervation. These results indicate clearly that the increases in lipogenic and thermogenic activities in IBAT in response to VMH stimulation are mediated by the sympathetic nerve supply of this tissue.