Effects of ventromedial hypothalamus stimulation on glycogenolysis in rat liver using in vivo microdialysis

In vivo microdialysis was applied to study the effects of ventromedial hypothalamus (VMH) stimulation on liver glycogenolysis under anesthesia. We examined glucose output and norepinephrine (NE) outflow from the liver through analysis of glucose and NE in the liver dialyzate. Stimulation of the VMH increased glucose output and NE outflow from the liver and increased the plasma glucose level. Similar results were obtained on hepatic nerve stimulation. Bilateral adrenalectomy did not abolish the glycogenolysis induced by VMH stimulation. NE outflow increased to a much greater extent in adrenalectomized rats. These data show that VMH stimulation causes glycogenolysis and glucose output from the liver mainly via the hepatic nerves, and that microdialysis is a simple and useful method for the study of liver metabolism in vivo.