Fj. Burczynski et al., INTRAHEPATIC BLOOD-FLOW DISTRIBUTION IN THE PERFUSED-RAT-LIVER - EFFECT OF HEPATIC-ARTERY PERFUSION, American journal of physiology: Gastrointestinal and liver physiology, 34(4), 1996, pp. 561-567
Variations in blood flow to different sinusoids within the liver can p
revent uniform uptake of solutes from plasma and contribute to cellula
r ischemia in low-flow states. However, the degree of variability and
the role of hepatic artery perfusion in maintaining uniform flow are p
oorly defined. We used an indicator dilution technique to compare the
distribution of sinusoidal transit times in isolated rat livers perfus
ed through the portal vein alone with livers perfused using both porta
l vein and hepatic artery. Physiological flow rates were used in each
case (1.2 +/- 0.3 ml . min(-1). g liver(-1)), but the second group rec
eived 32% of flow through the hepatic artery. Intralobular flow hetero
geneity was further assessed by gamma counting of small (similar to 10
0 mg) pieces of the liver after bolus injection of similar to 5 mCi of
a highly extracted compound ([I-125]triiodothyronine) into the portal
vein. Hepatic artery perfusion had no significant effect on mean sinu
soidal transit time or intrahepatic distribution volume for Cr-51-labe
led red blood cells or I-125-albumin. Analysis of the outflow profiles
indicated that hepatic artery perfusion did not affect transit time d
ispersion. However, heterogeneity of flow to individual portions of th
e liver, measured as the coefficient of variation, increased from 19 t
o 30%. These results indicate relatively uniform perfusion of the sinu
soids in the portally perfused rat liver and that additional perfusion
of the hepatic artery does not further improve hemodynamics. These re
sults have significance for the design and interpretation of transport
studies with the use of the perfused rat liver model.