The ability of the isolated Ringer-perfused frog liver, to concentrate dyestuffs in its secretion several hundred times, can be abolished entirely and reversibly by replacing in the Ringer solution about 1/8 of the NaCl by the isosmotic amount of a surface-inactive non-electrolyte (disaccharide, hexose, pentose, polyhydric alcohol, amino acid, acid amide) or electrolyte (salts of lower fatty acids, hydroxyl carboxylic, and dicarboxylic acids). This effect is not dependent upon changes in the perfusion rate.
The opposite effect, promotion of secretory activity, can be brought about by polar-non-polar electrolytes (salts of higher fatty acids, bile acids, and other aromatic carboxylic acids, aromatic sulfonic acids) and surface-active non-electrolytes (anesthetics, alkaloids, digitonin). However, reversibility of this effect cannot be regularly observed, since cytolysis is frequently the end result.
Suitable concentrations of inhibitory and promoting substances, simultaneously applied, counteract each other.
Inhibitory and promoting substances, in general, exhibit opposite effects upon the dispersion of colloids (starch, lecithin, gelatin).
The correlation between the physicochemical and the physiological action of the organic compounds is discussed.