Electrical stimulation of the distal cut end of the vagus nerves was performed at the diaphragmatic level in anesthetized dogs to study its effects on glucagon and insulin output from the pancreas. Stimulation of the dorsal vagus nerve increased both blood flow and plasma glucagon and insulin concentrations in the cranial pancre-aticoduodenal vein, resulting in a greater aug-mentation of bihormonal output. A significant enhancement was observed in femoral arterial plasma insulin, but not in circulating plasma glucagon. Plasma glucose concentration rose gradually during stimulation. Atropinization abolished the augmentation of glucagon and insulin output seen in response to stimulation of the dorsal vagus. Stimulation of the ventral vagus nerve resulted in no statistically significant increase in blood flow, plasma hormone concentration and plasma glucose level. These results indicate that physiological activation of the vagus nerve may regulate both insulin and glucagon secretion from the pancreas islet v...