Transport of tracer albumin (risa) from the peritoneal cavity to the plasma in the rat: role of diaphragmatic, visceral and parietal lymphatic pathways. Zakaria, El Rasheid, Ole Simonsen, Anna Rippe, and Bengt Rippe. Departments of Nephrology and Physiology, University Hospital of Lund, S-221 85 Lund, Sweden
APStracts 2:0448H, 1995.
Using a technique to acutely seal off various parts of the peritoneal membrane surface, with or without evisceration, we investigated the role of diaphragmatic, visceral and parietal peritoneal lymphatic pathways in the drainage of 125I-albumin (RISA) from the peritoneal cavity to the plasma during acute peritoneal dialysis in artificially ventilated rats. The total RISA clearance out of the peritoneal cavity (Cl) as well as the portion of this Cl reaching the plasma per unit time (ClP) were assessed. Under non-steady state conditions the Cl was five-fold higher than the ClP. Evisceration caused a 25-30 % reduction in both ClP and Cl. Sealing of the diaphragm, however, reduced the ClP by 55 % without affecting the Cl. A further reduction in the ClP was obtained by combining sealing of the diaphragm with evisceration, which again markedly reduced the Cl. However, the greatest reduction in the Cl was obtained when the peritoneal surfaces of the anterior abdominal wall (AAW) were sealed off in eviscerated rats. The discrepancy between the Cl and the ClP can be explained by the local entrance of fluid and macromolecules into peri-abdominal tissues, where fluid is rapidly absorbed through the capillary walls via the Starling forces, while macromolecules are accumulating due to their very slow uptake by tissue lymphatics under non-steady state conditions. Of the portion of the total Cl which rapidly entered the plasma, conceivably by lymphatic absorption, 55% could be ascribed to diaphragmatic lymphatics, 30% to visceral lymphatics, and only some 10-15% to parietal lymphatics. 

Received 19 May 1995; accepted in final form 26 September 1995.
APS Manuscript Number H471-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 November 95