Enterostatin efflux in cat intestinal lymph: relation to lymph flow, hyaluronan, and fat absorption

The question addressed in this study was whether enterostatin, the pancreatic procolipase activation peptide, modulates intestinal hyaluronan turnover via lymph. In anesthetized cats, segments of ileum were surgically isolated from the proximal and distal gut, the draining lymphatic was cannulated, and the segment was autoperfused in situ. In several groups, concentrations of immunoreactive enterostatin in lymph were compared with that in plasma at baseline and elevated lymph flow and in the absence and presence of fat absorption. The baseline ratio of lymph enterostatin to that in plasma (L/P) in the absence of fat absorption was 1.44 +/- 0.29 compared with 4.93 +/- 0.42 after cream feeding (P < 0.05). In a separate group, when the intestinal lumen was perfused for 2 h with a mixture of oleic acid and taurocholate, enterostatin L/P doubled compared with baseline. At high lymph flows, enterostatin concentrations fell in all groups, resulting in an L/P of 0.47 +/- 0.09 (P < 0.05) in the absence of fat absorption, 0.77 +/- 0.35 after oleic acid, and 1.26 +/- 0.13 in the cream-fed group. These changes correlate with the pattern of hyaluronan efflux from the ileum into lymph after fat absorption [R.K. Reed, M.I Townsley, V.H. Pitts, T.C. Laurent, and A.E. Taylor. Am. J. Physiol, 263 (Gastrointest. Liver Physiol. 26): G6-G11, 1992] However, in separate groups when enterostatin was introduced into ileum, either as a close intra-arterial bolus or via the intestinal lumen, there were no resultant changes in efflux of hyaluronan from the intestine into lymph. In conclusion, despite the fact that delivery of pancreatic exocrine secretions to the ileal lumen was blocked in this model, enterostatin concentration in lymph increased after fat absorption. Nonetheless, it seems clear that enterostatin does not modify intestinal hyaluronan turnover.