Pancreatic endocrine responses to stimulation of the peripheral ends of the vagus nerves in conscious calves.

1. The effects of stimulation of the peripheral ends of both vagus nerves below the heart (10 Hz for 10 min) were investigated in conscious calves 2-5 weeks after birth. 2. Stimulation was invariably below behavioural threshold and caused a prompt increase in the concentrations of pancreatic glucagon, insulin and pancreatic polypeptide (PP) in the arterial plasma. Each of these responses was blocked by pretreatment with atropine (0.2 mg/kg). 3. Administration of exogenous glucose by continuous I.V. infusion (ca. 0.08 mmol kg-1 min-1) greatly enhanced the release of insulin in response to vagal stimulation without significantly changing that of pancreatic glucagon or PP. 4. Vagal stimulation also caused a significant rise in the concentration of vasoactive intestinal peptide (VIP) in the intestinal lymph and this response was found to persist in the presence of atropine.