AJP - Heart and Circulatory Physiology, Vol 258, Issue 6 1650-H1654, Copyright © 1990 by American Physiological Society
Microvascular permeability to endogenous plasma proteins in the jejunum
N. A. Mortillaro and A. E. Taylor
Department of Physiology, College of Medicine, University of South Alabama, Mobile 36688.
Steady-state lymph flow and lymph (CL) and plasma (CP) protein
concentrations were measured at venous outflow pressures of 0, 10, 20, and
30 mmHg in an autoperfused segment of cat jejunum. In addition to
determining total protein concentrations in lymph and plasma,
polyacrylamide gradient gel electrophoresis was used to determine lymph and
plasma protein concentrations of albumin and nine other plasma proteins.
The osmotic reflection coefficient (sigma d) for total proteins, albumin,
and each of the nine protein fractions was estimated using CL/CP at a
capillary filtration rate independent state, when 1 - CL/CP = sigma d. A
sigma d of 0.83 was obtained for total proteins, a value similar to that
reported for both dog jejunum and descending colon (0.85) but appreciably
different from that reported for both cat stomach (0.78) and ileum (0.92).
Additionally, sigma d for albumin and each of the nine plasma protein
fractions (molecular radii ranging from 37 to 120 A) increased as molecular
radius increased. A two-pore model composed of a ratio of 3,750 48-A radius
small pores to one 250-A radius large pore describes the data obtained,
with 82% of the total volume flow occurring through the small pores and 16%
through the large pores.
