AJP - Gastrointestinal and Liver Physiology, Vol 252, Issue 5 602-G606, Copyright © 1987 by American Physiological Society
Lymph protein concentration in initial and collecting lymphatics of the rat
D. C. Zawieja and B. J. Barber
Lymph samples were obtained from villus initial and mesenteric prenodal
collecting lymphatics of the anesthetized rat using standard micropuncture
techniques. The protein concentrations of the lymph samples were determined
using a fluorometric microassay. These procedures were performed on
preparations either superfused with a modified Krebs solution or covered
with paraffin oil. The protein-concentrating ability of the intestinal
lymphatics was evaluated to test the osmotic theory of lymph formation. The
mean initial lymph protein concentration in superfused preparations was
2.08 g/dl (SE = 0.20). The lymph protein concentration in collecting
vessels in superfused preparations was 2.20 g/dl (SE = 0.19). The protein
concentration from initial lymphatics in oil-covered preparation was 2.48
g/dl (SE = 0.17). The lymph protein concentration in collecting vessels in
oil-covered preparations was 2.32 g/dl (SE = 0.15). The difference between
initial and collecting lymph protein concentration found was an order of
magnitude lower than that predicted by the osmotic theory. These results
cast serious doubts on the effectiveness of the osmotic mechanism of lymph
formation as it is presently defined.
