Impaired response of pancreatic polypeptide to hypoglycaemia: an early sign of autonomic neuropathy in diabetics.

The pancreatic polypeptide (PP) response to insulin-induced hypoglycaemia was studied in 18 juvenile diabetics and was calculated as the difference between the prestimulatory PP concentration and the maximal concentration measured. The response was severely impaired in patients with autonomic neuropathy (mean +/- SE of mean 22 +/- 12 pmol/l) as compared with patients without neuropathy (252 +/- 51 pmol/l). Patients whose diabetes was of only a few years' duration showed a normal PP response to hypoglycaemia, and the response diminished significantly with increasing duration of diabetes. The decreased PP response to hypoglycaemia was significantly correlated with an increased threshold of the sense of vibration, (rs = 0.86). These results suggest that impaired, secretion of PP may serve as an early sign of autonomic neuropathy in diabetes.