The effect of adrenergic and cholinergic mechanisms on the secretion of pancreatic polypeptide and gastrin following hypoglycaemia in man.

The changes of plasma pancreatic polypeptide (PP) and plasma gastrin following acute insulin-induced hypoglycaemia (0 . 15 U/kg) were examined in six normal subjects, six tetraplegic subjects (preganglionic sympathectomy) and six tetraplegic subjects given atropine (combined adrenergic denervation and cholinergic blockade). Adequate hypoglycaemia was achieved in all three groups. The normal rise of plasma PP following hypoglycaemia was present in the tetraplegic group without atropine but was abolished in the tetraplegic subjects given atropine. There was no significant rise in plasma gastrin following hypoglycaemia except in the tetraplegic group given atropine. These results confirm that the secretion of PP in response to acute hypoglycaemia is mediated via cholinergic activity, while gastrin secretion appears to be inhibited in normal subjects by a vagal cholinergic mechanism.