Effects of galanin and calcitonin gene-related peptide on insulin and glucagon secretion in man.

To study the influence of the pancreatic neuropeptides, galanin and calcitonin gene-related peptide, on insulin and glucagon secretion in man, synthetic porcine galanin (80 pmol.kg-1.min-1; N = 6) or synthetic human calcitonin gen-related peptide (10 pmol.kg-1.min-1; N = 5) was infused intravenously in human volunteers. Following 5 min of infusion, arginine (5 g bolus + 10 mg.kg-1.min-1) was given. Galanin did not affect basal or arginine-stimulated insulin secretion judged from determinations of plasma insulin and C-peptide. Similarly, galanin did not affect arginine-stimulated glucagon secretion. Calcitonin gene-related peptide did not affect basal or arginine-stimulated insulin or glucagon secretion. However, calcitonin gene-related peptide slightly potentiated the arginine-induced hyperglycemia (p less than 0.01). Thus, in man, galanin has no influence on insulin or glucagon secretion when infused at 80 pmol.kg-1.min-1, whereas CGRP at 10 pmol.kg-1.min-1 induces slight hyperglycemia.