ENTEROSTATIN EFFLUX IN CAT INTESTINAL LYMPH - RELATION TO LYMPH-FLOW,HYALURONAN, AND FAT-ABSORPTION

The question addressed in this study was whether enterostatin, the pan creatic procolipase activation peptide, modulates intestinal hyalurona n turnover via lymph. In anesthetized cats, segments of ileum were sur gically isolated from the proximal and distal, gut, the draining lymph atic was cannulated, and the segment was autoperfused in situ. In seve ral groups, concentrations of immunoreactive enterostatin in lymph wer e 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 absor ption was 1.44 +/- 0.29 compared with 4.93 +/- 0.42 after cream feedin g (P < 0.05). In a separate group, when the intestinal lumen was perfu sed for 2 h with a mixture of oleic acid and taurocholate, enterostati n L/P doubled compared with baseline. At high lymph flows, enterostati n 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 o leic acid, and 1.26 +/- 0.13 in the cream-fed group. These changes cor relate 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 Ph ysiol. 26): G6-G11, 1992]. However, in separate groups when enterostat in was introduced into ileum, either as a close intra-arterial bolus o r via the intestinal lumen, there were no resultant changes in efflux of hyaluronan from the intestine into lymph. In conclusion, despite th e fact that delivery of pancreatic exocrine secretions to the ileal lu men was blocked in this model, enterostatin concentration in lymph inc reased after fat absorption. Nonetheless, it seems clear that enterost atin does not modify intestinal hyaluronan turnover.