Nitrogen absorption in pancreatectomized patients: protein versus protein hydrolysate as substrate.

To investigate nitrogen absorption in the absence of the pancreas, six patients with total pancreatectomy, all in stable nutritional and metabolic condition, underwent two periods of enteral nutrition identical in all respects except for the nitrogen source. Nitrogen source was either lactalbumin or its hydrolysate. The quantity and quality of calories infused simulated the patient's usual diet, which was a high-protein diet (2.0 +/- 0.4 gm/kg body weight). Pancreatic enzyme replacement therapy was discontinued during each period of enteral nutrition. All patients had greater nitrogen absorption during the enteral nutrition with lactalbumin hydrolysate than that with lactalbumin (91% +/- 2% vs 61% +/- 6% of nitrogen intake, p less than 0.02). Despite this difference in absorption, nitrogen balances during the two periods of enteral nutrition were not significantly different. This appeared to be caused by a urea production rate that was greater during the enteral nutrition with lactalbumin hydrolysate than the rate during that with lactalbumin (26 +/- 1 gm/24 hr vs 16 +/- 3 gm/24 hr, p less than 0.05). Plasma concentrations of amino acids and proteins did not differ significantly during the two treatments. In conclusion, the data suggest that (1) the intestine plays a significant role in protein digestion and that (2) enteral feeding with a protein hydrolysate could eliminate the need for a high-protein diet in patients with pancreatic insufficiency.