The parotid and the pancreas.

Parallel studies in parotid and pancreatic function and histology were carried out in Thomas fistula dogs with irradiation-induced chronic pancreatitis. After completion of base line studies of parotid and pancreatic secretion, four dogs were subjected to 2,400 rads tumor dose over two weeks (with a nominal single dose of 1,175 rets); two additional dogs served as control. Sequential studies were performed on pancreatic secretion in response to secretin and on parotid secretion in response to urecholine. After a short-lived period of hypersecretion. There was a progressive reduction in pancreatic secretory rate, bicarbonate and enzyme outputs (greater than 90% after three months). Parotid secretion increased over this period but subsequently decreased, so that at eight months there was a marked reduction both in pancreatic and parotid function. Whereas pancreatic histology showed diffuse interstitial fibrosis and reduction of acinar tissue, no histologic changes were noted in the parotid glands. Although the mechanisms are unclear, alterations in parotid secretion may be of value in the diagnosis of chronic pancreatitis, in the evaluation of its severity, and may yield information on the duration of the disease.