Authors: G Szabo ( ) , E Anda ( ) , E Vandor ( )
Muscle activity (electrical stimulation of the muscles of the posterior extremity) in dogs with thoracic duct fistula did lead to a fivefold increase of the LOH-activity in leg lymph. A significant increase of enzyme activity was observed also in blood serum. It is concluded, that the enzyme protein is transported from the tissues during muscle activity not exclusively by the lymphatics but also by the veins.
The view, that protein molecules are transported from tissues to the blood stream exclusively by the lymphatic vessels is more or less generally accepted (1, 4). It was however shown that colloides injected into some tissues are to a considerable extent absorbed also by the blood capillares (2, 8). The objection can nevertheless be raised, that in these experiments the colloidal substances were actually driven by the injection pressure through the damaged capillary wall into the vessel lumen.
The activity in blood plasma of the cytoplasmic enzyme lactate dehydrogenase is markedly increased in various pathologic conditions. In these states the enzyme enters into the circulation in consequence of cellular damage or increased membrane permeability. Plasma LDH level is however raised also by hypoxia and muscular activity (3, 6, 7, 11). There is no evidence for the damaging effect of muscular exercise to the capillary wall. Accordingly, LDH leaking during muscle activity into the intercellular fluid may be a suitable molecule for the study of protein transport from the tissues. LDH has the further advantage that its source can be traced back to the tissue of origin by separating electrophoreticaly the component isoenzymes. As it is well established, the individual tissues show a specific isoenzyme pattern and in pathologic conditions the enzyme from the damaged tissues does not only increase LDH activity in plasma but also procedures a characteristic shift in the LDH-isoenzyme pattern (5, 13, 14, 16).
In the experiments to be reported the effect of muscular activity on lymphatic and plasma enzyme activity and LDH-isoenzyme pattern was studied in dogs. Consequently it could be shown that the enzyme protein is transported from the activity tissues by lymphatic as well as by venous channels.
How to Cite: Szabo, G. , Anda, E. & Vandor, E. (1972) “The Effect of Muscle Activity on the Lymphatic and Venous Transport of Lactate Dehydrogenase”, Lymphology. 5(3).