Pancreatic exocrine secretion in the rat after chronic alcohol ingestion: nonparallel secretion of proteins and pancreatic secretory trypsin inhibitor

Abstract

Pancreatic secretion was studied in rats given 20% (v/v) ethanol or water ad libitum for 7--8 months. Basal secretion samples were collected for 30 min, after which secretion was stimulated with secretin (1.1 U/h) and cholecystokinin-pancreozymin (2.8 U/h). Then, four successive 30-min samples were collected. The flow rate, protein concentration and output, pancreatic secretory trypsin inhibitor (PSTI) concentration and output, and chymotrypsinogen concentration increased significantly from basal levels during the first stimulation period in both groups, with no significant differences between the groups. During the second, third, and fourth stimulation periods gradual decreases of these parameters were observed in both groups, and the decrease of volume, protein output, and PSTI output were significantly greater in the alcohol group than in the control group. No significant differences were observed in the concentrations of chymotrypsinogen, protein, and PSTI, but the PSTI/protein ratio was significantly lower in the alcohol group at the end of the experiment. The concentrations of bicarbonate did not decrease during stimulation and were elevated in the alcohol group compared with the control group during the fourth period. It is suggested that the decreased PSTI/enzyme ratio caused by long-term alcohol ingestion might favour premature activation of the proenzymes in the pancreatic ducts.