The Effect of Total Parenteral Nutrition or Elemental Diet on Pancreatic Proteolytic Activity and Ultrastructure

Abstract

Previous reports regarding the effect of an elemental diet (ED) on pancreatic secretion have been conflicting. This study was designed to assess the effect of a high-nitrogen ED or total parenteral nutrition (TPN) on proteolytic activity in the pancreatic exocrine cell. Forty-eight dogs were divided into 12 groups of 4 each. Group I (control) was fed commercial dog food. Groups II, III, and IV received 1, 2, and 3 days, respectively, of 25% glucose with 4.25% amino acids. Groups V, VI, and VII received 1, 2, and 3 days, respectively, of 25% glucose with 2.75% amino acids. Groups VIII, IX, and X received 3 days of ED given orally, via gastrostomy or jejunostomy, respectively. Groups XI and XII received 1 day each of either 2.75% amino acids or 25% glucose. The pancreas of each dog was then resected and processed for electron microscopy, or minced and analyzed for tryptic activity expressed as micro-moles of benzoyl arginine ethyl ester (BAEE) digested per milligram of pancreatic protein. There were no significant differences in ultrastructure or in the levels of pancreatic tryptic activity between the control and the 11 experimental groups. It appears that during the short period of our treatment with TPN as well as with ED, the exocrine cell retains its normal content of proteolytic enzyme. Reports of others that pancreatic secretion volume decreases with TPN and ED, coupled with our findings of stable intracellular tryptic activity, indicate that the synthesis and release of proteolytic enzymes have actually been reduced by TPN and ED. Thus, TPN or ED should benefit the patient with pancreatitis by decreasing pancreatic secretion as well as pancreatic proteolytic enzyme synthesis.