Abstract
Activity of stellate cells in the liver ordinarily is tested by their capacity to incorporate microscopic or submicroscopic particles, e. g., colloidal trypan blue. In isolated perfused frog liver this uptake is shown to be an active process by the fact that it is reversibly suppressed by addition to the perfusion fluid of an anesthetic or of iodoacetic acid. 1 Also, the color uptake is stopped by perfusing, for a short time, with Ringer's solution, but reappears upon the addition of serum or of various protein bodies. 2 3 1 While studying the influence of surface-active and nonpolar-polar organic compounds on erythrocytes, muscles, nerves, liver, kidney, 4 we were reminded of the statement of A. J. Clark 5 that the strikingly beneficial effect of serum on the heart of a frog, which has become hypodynamic by a prolonged perfusion with Ringer, is due chiefly to presence of minute amounts in the serum of lipoids and soaps. We decided to study the influence of physico-chemically similar compounds upon the activity of the stellate cells.
Methods. The liver of female frogs was perfused through the abdominal vein with buffered Ringer solution (pH 7.5). In general, after 30 min. 2% ox serum was added, 10 min. later 0.02% trypan blue and a specified amount of a test substance were added. After another 45 min. the liver was placed in formalin and cut by a freezing microtom. In each experiment 2 to 4 frogs of approximately the same weight and belonging to the same group were compared. The same fresh stock of serum was used for all the perfusions in each experiment to avoid error resulting from varying amounts of activating substances in the sera.
Results. With livers identically treated the uptake of color varies very much, mainly because of seasonal variations.
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