AJP - Regulatory, Integrative and Comparative Physiology, Vol 268, Issue 3 715-R722, Copyright © 1995 by American Physiological Society
Role of intestinal fluid in restitution of blood volume and plasma protein after hemorrhage in awake rats
D. N. Darlington, R. O. Jones, T. A. Magnuson and D. S. Gann
Department of Surgery, University of Maryland Medical School, Baltimore 21201.
To determine whether food and/or water in the gastrointestinal tract
affects restitution of blood volume and plasma protein after hemorrhage,
fed and 24-h-fasted awake rats received a 20 ml.kg-1 x 3 min-1 hemorrhage,
and restitution of blood volume was measured by Evans blue dye and dilution
of hematocrit. Restitution of blood volume and plasma protein in fed rats
was complete by 2-4 h. In contrast, restitution was severely attenuated in
fasted rats and was not complete by 24 h. Because initial blood volume was
significantly lower in the fasted rats (55.4 +/- 1.7 vs. 64.9 +/- 2.5 ml/kg
in fed), the percent blood lost during hemorrhage was significantly greater
(36 vs. 31%). However, the attenuated restitution was not the result of the
larger hemorrhage, as fed rats receiving a 36% hemorrhage also restored
blood volume completely by 4 h. In fasted rats, complete restitution of
blood volume did occur when either water or food and water were given 4 h
after hemorrhage. Gastrointestinal water content fell (from 65.5 +/- 4.8 to
47.9 +/- 1.6 ml/kg) 2h after hemorrhage in fed but not in fasted rats (33.5
+/- 2.4 to 30.6 +/- 2.5 ml/kg). These data suggest that gastrointestinal
fluid is essential for complete restoration of blood volume in the awake
rat.
