THE INFLUENCE OF ABSORPTION/ENTEROSORPTION AND PARTIAL OCCLUSION OF THE PORTAL VEIN ON THE QUANTITY AND COMPOSITION OF THE INTESTINAL LYMPH

Abstract

What influence does the admixture of absorbed
water exert on the rate of flow and composition
of the lymph? To analyse this question rats were
given twice distilled water 20 ml/kg intraduodenally.
As a result of this fluid loading, lymph flow
rosa to approx. 400% of its initial value, and this
lymphagogue reaction lasted some 30 min. There
was a time-related decrease in PVP filtration coefficient
end in the total density and the protein
content of the lymph. However, the decrease in
these values was less than would have been expected
from the "dilution effect" caused by the absorption
of the water.
After lntraduodenel instillation of mannitol solution
(six times isotonic in relation to blood} in a
dose of 7 ml/kg there was enterosorption of water
out of the blood into the intestinal lumen, or in
other words this induced a reverse flow of water
~ga l nst the direction of intestinal absorption. As
might be expected, the quantity of intestinal lymph
diminished, while the PVP filtration coefficient
end the density and protein content of the lymph
rose, though once again less than would have been
expected from the decrease in lymph flow.
Aller partial occlusion of the portal vein for 10
min lymph flow rose to an average of seven times
its initial value. Under these conditions there was
elso a decrease in the PVP filtration coefficient
end In the density and protein content of the
lymph, which once again was less than might have
been expected from the increase in lymph flow.
Intestinal lymph occupies a special position among
the lymphs produced by the organs of the body
in that it is derived from two sources: capillary
filtration and absorbed water. In view of the behaviour
of the PVP filtration coefficient and the density
and protein content of the lymph under various
conditions - absorption of protein-free water, enterosorption
of fluid from the blood into the intestinal
lumen, and partial occlusion of the portal vein
(which raises capillary filtration pressure} - It
seems implausible that the plasma-lymph barrier
can be envisaged merely as a simple membrane with
pores and leaks. The concept of a matrix-like layer
seems to offer a much better explanation of the
experimental results.