Ventromedial hypothalamic stimulation enhances peripheral glucose uptake in anesthetized rats

Effects of electrical and chemical stimulation of the ventromedial (VMH) and lateral hypothalamic (LH) nuclei on glucose uptake in peripheral tissues were studied by the 2-deoxy-D-[3H]glucose (2-[3H]DG) method in anesthetized rats. Electrical stimulation of the VMH increased the rate constant of glucose uptake in brown adipose tissue (BAT; 8 times), heart (3 times), and skeletal muscles (1.5 times) but not in white adipose tissue, diaphragm, and brain, without detectable changes in plasma insulin levels. Chemical stimulation of the VMH by microinjection of L-glutamate also enhanced the rate constant of glucose uptake in BAT, heart, and skeletal muscles preferentially, which indicates that the enhancement of glucose uptake in these tissues is derived from activation of VMH neurons. The increased rate of glucose uptake in BAT in response to VMH stimulation was effectively suppressed by surgical sympathetic denervation, suggesting a mediation of the sympathetic nerve in this effect. On the other hand, electrical stimulation of the LH had no appreciable effect on 2-[3H]DG uptake in any tissues. It is concluded that glucose uptake in certain peripheral tissues is accelerated selectively by activation of VMH neurons, the action of which is independent of plasma insulin but which is probably via the sympathetic nervous system.