Acceleration of pancreatic regeneration by cholecystokinin in rats

Groups of well-fed adult male rats were either killed at the start of the experiment (initial controls) or injected (i.p.) daily for 8 days with DL-ethionine (700 mg/kg) while being fed a protein-free diet to achieve degeneration of the exocrine pancreas. Some animals were killed on the ninth day (degeneration group) while others were fed a commercial rat-chow pellet containing 24% protein for the next 7 days (regeneration period), during which period they were infused subcutaneously (osmotic minipump) with either saline or CCK-8 (300 ng or 600 ng/kg/h). These animals were then killed. Pancreata from all groups were assayed for various parameters of growth as well as for trypsin and chymotrypsin activities. At the end of the degeneration period, pancreatic weight and DNA and protein content of the pancreas (expressed as mg/100 g body weight) were significantly decreased by 62, 47, and 80%, respectively, when compared with the corresponding controls. Pancreatic thymidine kinase (TK), trypsin, and chymotrypsin activities were also found to be significantly lower in the degeneration group than in the initial controls. Regeneration of the pancreas (end of the 7-day experimental period) in the saline-infused group was associated with a significant increment in pancreatic weight, protein content, and the activity of trypsin and chymotrypsin in the pancreas, without affecting DNA content and TK activity when compared with the degeneration group.(ABSTRACT TRUNCATED AT 250 WORDS)