Stimulation of human pancreatic polypeptide secretion by hypoglycemia is independent of adrenergic mechanisms

Human pancreatic polypeptide (HPP) increases after insulin-induced hypoglycemia. To determine whether ad-renergic mechanisms contribute to this increase in normal man, six subjects were studied on two occasions: once after insulin alone and once after insulin plus simultaneous α (phentolamine)-and β (propranolol)-adrenergic blockade. Despite comparable hypoglycemia (51 ± 4 vs. 49 ± 4 mg/dl), the increase in HPP did not differ in the presence or absence of adrenergic blockade (721 ± 215 vs. 736 ± 193 pg/ml, respectively). These findings suggest that HPP secretion during hypoglycemia is not dependent on adrenergic mechanisms.