M. Kim et al., BLOOD-FLOW LIMITATIONS OF SOLUTE TRANSPORT ACROSS THE VISCERAL PERITONEUM, Journal of the American Society of Nephrology, 8(12), 1997, pp. 1946-1950
In a previous study, no limitations to urea transfer across the pariet
al peritoneum were demonstrated with decreases in local blood flow of
70%. It was hypothesized that the visceral peritoneum would have simil
ar characteristics. To address this problem at the tissue level, diffu
sion chambers were affixed to the serosal side of the stomach, cecum,
or liver of anesthetized rats (n = 6 each tissue), and solutions conta
ining C-14 urea were placed in the chamber. During each experiment, th
e local chamber blood flow was measured with laser Doppler flowmetry,
and, simultaneously, the disappearance of the tracer versus time was d
etermined under three conditions: control, after 60 to 70% blood flow
reduction, and postmortem (flow = 0). The results showed no difference
in the urea mass transfer coefficient (MTC; mean +/- SEM; cm/min x 10
(3)) between control and blood flow reduction for the stomach (4.0 +/-
0.4 versus 3.6 +/- 0.3) or for the cecum (4.6 +/- 0.3 versus 4.0 +/-
0.3). However, the MTC was significantly decreased by local blood flow
reduction in the liver (5.4 +/- 0.2 versus 2.6 +/- 0.2). Postmortem d
ata demonstrated significant reductions in the MTC with blood flow equ
al to zero. It is concluded that a 60 to 70% blood flow reduction from
control values does not limit solute transperitoneal transfer in the
hollow viscera but causes significant changes in the mass transfer acr
oss the liver surface. Because the liver makes up only a small portion
of the effective exchange area, overall transperitoneal solute transf
er should not be greatly affected by significant decreases in blood fl
ow.