AJP - Heart and Circulatory Physiology, Vol 244, Issue 4 495-H504, Copyright © 1983 by American Physiological Society
Blood flow and norepinephrine effects on liver vascular and extravascular volumes
D. Cousineau, C. A. Goresky and C. P. Rose
The relative effects of changes in hepatic blood flow and in levels of
sympathetic activity on liver volumes were ascertained by use of
multiple-indicator dilution studies. Portal vein-hepatic vein dilution
patterns were obtained following injection of a mixture containing
51Cr-labeled red blood cells (a vascular reference) and 14C-labeled sucrose
(a reference extracellular substance). Hepatic blood volume was calculated
as the product of liver blood flow and red cell transit times, and
interstitial space as the product of plasma flow and the difference between
labeled sucrose and red cell transit times. Concentrations of
norepinephrine and epinephrine were measured in aorta, portal vein, and
hepatic vein. Hepatic blood volume and interstitial space increased with
increased blood flow; and elevated plasma norepinephrine levels, especially
in portal vein (following either exogenous infusion or activation of
peripheral sympathetic fibers) selectively reduced the distending effect of
hepatic inflow on the vascular volume. The data provide a description of
the in vivo variation in canine liver vascular and interstitial volumes
with blood flow and sympathetic activation.
