Plasma anp levels and protein extravasation during graded expansion
with equilibrated whole blood.
Tucker, V. L.
Department of Human Physiology, University of California, Davis, CA
95616
APStracts 3:0109R, 1996.
The relationship between plasma immunoreactive atrial natriuretic
peptide (irANP) and radiolabeled albumin clearance (CBSA) into
multiple tissues following graded volume stimuli was examined. To
obtain a pure volume stimulus, pentobarbital anesthetized rats (5 or
6 per group) were equilibrated with a reservoir of blood by a femoral
arteriovenous shunt and volume expansion (VE) was produced by
adjusting reservoir outflow. Peak increases in CVP during VE equal to
2% and 3% of the body wt over 5 min were 3.6 0.2 and 7.0 0.3 mm Hg
and plasma irANP levels measured at 40 min post-VE were elevated 1.9
and 4.1-fold above baseline, respectively. Graded increases in CBSA
measured between 5-35 min post-VE occurred in selective tissues,
including intestine, visceral fat, lung and muscle (P 0.05). In
separate animals, the level of VE was maintained after 2% VE by
slower administration of an additional 2% VE for the remaining 30
min. This resulted in a more sustained CVP elevation and larger
increases in irANP levels and CBSA compared to either 2 or 4% VE.
Furthermore, equations derived from previous work in this laboratory
involving intravenous administration of ANP predicted the magnitude
of CBSA elevation during maintained VE. These findings support a role
for ANP in regulating transcapillary protein distribution during
acute intravascular expansion.
Received 30 May 1995; accepted in final form 13 March 1996.
APS Manuscript Number R322-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 27 March 96