beta-Endorphin-induced hyperglycemia is mediated by increased central sympathetic outflow to adrenal medulla

Synthetic human beta-endorphin increased plasma glucose concentration when administered intracisternally in chronically cannulated, conscious, unrestrained, adult male rats. This hyperglycemic effect of beta-endorphin was blocked by prior systemic administration of naloxone, supporting mediation of the effect at opioid receptors in brain. Adrenal denervation blocked the beta-endorphin-induced increase in plasma glucose, supporting a thesis that this effect is mediated at least in part by increased epinephrine secretion. The hyperglycemic response to intracerebral beta-endorphin was also blocked by either intracerebral hemicholinium-3 or somatostatin, supporting both a cholinergic link and a somatostatin neuron in the brain mechanism regulating endorphin-induced stimulation of sympathetic outflow.