trypsinogen and Hyperplasia

The present study was performed to examine the effect of ageing on pancreatic hyperplasia observed after proximal small bowel resection (PSBR). Young and old Wistar rats were randomly assigned to two groups, which underwent either an approximate 90% PSBR or a jejunal and ileal transection (TRC). One week after the operation, the pancreatic wet weight and the protein, DNA and RNA content of the pancreas were all significantly higher in young PSBR rats than in young TRC rats. However, no differences were seen in the old rat groups. Plasma enteroglucagon levels were elevated in both young and old PSBR rats, but the ratio of increase between the PSBR and TRC groups was significantly higher in young rats. Plasma cholecystokinin and gastrin levels did not increase after PSBR in either the young or old rats. These findings suggest that pancreatic hyperplasia observed after PSBR is attenuated by ageing, probably due to an insufficient increase in plasma enteroglucagon levels.

Topics: Aging; Amylases; Animals; Body Weight; Cholecystokinin; DNA; Eating; Gastrins; Glucagon-Like Peptides; Hyperplasia; Intestine, Small; Lipase; Male; Organ Size; Pancreas; Radioimmunoassay; Rats; Rats, Wistar; RNA; Trypsinogen

Topics: Amylases; Animals; DNA; Hyperplasia; Hypertrophy; Lipase; Male; Pancreas; Rats; Rats, Inbred Strains; Trypsin Inhibitors; Trypsinogen

Rats were given injections of caerulein, secretin, or a combination of these two peptides subcutaneously 3 times daily for 5, 10, or 15 days. Caerulein produced significant dose- and time-dependent increases in pancreatic weight and content of DNA, RNA, protein, amylase, and trypsinogen. Secretin produced significant increases in pancreatic weight and content of RNA and lipase after 15 days of treatment. After only 5 days of treatment with a combination of secretin plus caerulein, pancreatic weight and content of RNA and protein more than doubled, and trypsinogen content increased more than fivefold. Comparing the averages across the 5-, 10-, and 15-day values, increases in weight, protein, and trypsinogen with the combination of secretin plus caerulein were significantly greater than the sum of the effects of the peptides given singly. Using increase in DNA content as an index of hyperplasia and increases in the ratios of pancreatic weight, RNA content, and protein content to DNA content as indices of hypertrophy, we concluded that caerulein produced both hyperplasia and hypertrophy of rat pancreatic acinar cells. Secretin markedly augmented the hypertrophic action of caerulein but did not alter its hyperplastic action.

Topics: Amylases; Animals; Cell Division; Ceruletide; Dose-Response Relationship, Drug; Drug Therapy, Combination; Hyperplasia; Hypertrophy; Lipase; Male; Pancreas; Rats; Secretin; Trypsinogen