AJP - Heart and Circulatory Physiology, Vol 242, Issue 6 1044-H1049, Copyright © 1982 by American Physiological Society
Effects of increased venous pressure on albumin- and IgG-excluded volumes in muscle
D. R. Bell and R. J. Mullins
The effect of elevated venous pressure on the extravascular distribution
space of albumin and gamma-immunoglobulin G (IgG) in muscle was studied in
anesthetized rabbits. In nine rabbits, venous pressure in one leg was
increased from 8 to 28 mmHg while the other leg served as a control.
Samples of plasma and prenodal muscle lymph were collected for 4 h before
taking samples of the gastrocnemius muscle. Lymph was collected from a
femoral lymphatic after ligating the popliteal efferent lymphatic. The
extracellular and plasma spaces in the tissue samples were measured using
51Cr-labeled ethylenediaminetetraacetic acid (EDTA) and 125I-human serum
albumin, respectively. The protein spaces were calculated from measurements
of endogenous albumin and IgG concentrations using rocket
electroimmunoassay. Albumin and IgG were both excluded from 50% of the
interstitial space at lymph concentration. After venous congestion, the
interstitial volume was twice that of control. Lymph flow increased from
0.82 +/- 0.18 to 4.44 +/- 0.64 microliters/min. The extravascular mass of
albumin and IgG increased. There was no change in the excluded volume
fraction for albumin but a decrease in that for IgG. Changes in
interstitial protein exclusion in skeletal muscle after pressure elevation
may not be important in oncotic buffering of the edema.
