AJP - Heart and Circulatory Physiology, Vol 248, Issue 1 15-H25, Copyright © 1985 by American Physiological Society
Exchange of macromolecules between peritoneal cavity and plasma
M. F. Flessner, R. L. Dedrick and J. S. Schultz
The exchange of fluorescein isothiocyanate-labeled dextrans ranging in
weight-averaged molecular weight from 19,400 to 160,000 and 125I-bovine
serum albumin (BSA) between dialysis fluid (5% BSA in Krebs-Ringer
solution) in the peritoneal cavity and the plasma was studied in
anesthetized female Sprague-Dawley rats. Plasma and peritoneal samples were
collected for 3-4 h after either 1) an intraperitoneal injection of
dialysis fluid with tracer or 2) an intravenous injection of tracer
material simultaneously with an intraperitoneal injection of dialysis
solution without tracer. Analysis of the data by means of a mathematical
model of the transport process suggests a functional asymmetry in transport
of large molecules across the blood capillary wall. Substances injected
intravenously have a net transport from the blood capillaries to the
peritoneal cavity. Substances of molecular weight greater than or equal to
39,000 transport from the cavity to the plasma via peritoneal lymphatics;
19,400 molecular-weight dextran transports from the cavity to the plasma
primarily via lymphatics with some blood capillary uptake. Tissue
diffusivities and capillary mass transport coefficients are derived for the
substances tested.
