This study was designed to determine the effects of neural isolation of the jejunoileum (a model of intestinal transplantation) on jejunal absorptive function and associated changes that might occur over time. Net absorption of a simple, balanced crystalloid solution perfused in an 80 cm enterically isolated jejunal loop was assessed in two groups of conscious dogs with neurally intact jejunal loops or neurally isolated jejunal loops. Experiments were conducted 2, 4, and 8 weeks after surgery during fasting and after feeding to determine temporal changes. Net absorption of water and electrolytes (sodium, potassium, and chloride), glucose, and folate and loop transit times were not different (p greater than 0.05) between groups at any time point despite the presence of ongoing watery diarrhea and weight loss (15% +/- 8% body weight) in the dogs with neurally isolated jejunoileum. The effects of neural isolation (extrinsic denervation and disruption of enteric neural continuity and lymphatic drainage) do not appear to decrease net absorptive capacity for water, electrolytes, simple sugars, or folate when evaluated between 2 and 8 weeks after neural isolation. The watery diarrhea and weight loss do not appear to be related to a jejunal secretory diarrhea. These findings may have important implications in the transplanted small intestine.