Pancreatic polypeptide secretion. A marker for disturbed pancreatic function in cystic fibrosis.

Pancreatic polypeptide, a 36-amino peptide, is released from the pancreas by a variety of stimuli, including intravenous Boots secretin. Studies in a generalized destructive and inflammatory process such as chronic pancreatitis have revealed a markedly diminished response to stimulation. To assess whether pancreatic polypeptide release in response to Boots secretin provides a useful measure of pancreatic destruction in cystic fibrosis, 41 patients with proven cystic fibrosis, aged 14 months-23 years, and seven control subjects, aged 18-24 years were studied. Serum pancreatic polypeptide, measured by radioimmunoassay, rose from a basal of 18.5 +/- 2.7 pmol/liter to a peak of 35.6 +/- 4.3 pmol/liter at 5 min in cystic fibrosis, and from a basal of 10.8 +/- 2.8 pmol/liter to a 5-min peak of 109 +/- 27.7 pmol/liter in control subjects. The basal levels of both groups were similar but the cystic fibrosis patients had a significantly lower peak response than controls (P less than 0.05). The peak over basal pancreatic polypeptide ratio was calculated and was less than five in 93% of cystic fibrosis patients, whereas all control subjects had a ratio greater than five. Pancreatic polypeptide measurements in response to secretin may be a convenient and useful means of following the course of pancreatic disease in a chronic illness such as cystic fibrosis.