THE PHYSIOLOGICAL ACTION OF THE PRINCIPLES ISOLATED FROM THE SECRETION OF THE EUROPEAN GREEN TOAD (BUFO VIRIDIS VIRIDIS)

¹ From the Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, and the Laboratory of Endocrine Research, Johns Hopkins University, Baltimore

From the parotid secretion of the European green toad, Bufo viridis viridis, the following principles have been isolated and studied pharmacologically:

a. Cholesterol, which is admixed with 3 parts of ergosterol per thousand as proved spectrographically.

b. Virido-bufagin, C₂₃H₃₄O₅, which has a digitalis-like action. The average fatal dose in cats (determined on 10 animals) is 0.11 mgm. per kilogram. The minimal emetic dose in pigeons is 0.15 mgm., and that in cats, 0.06 mgm. per kilogram.

c. Virido-bufotoxin, C₃₇H₆₀O₁₀N₄, which has an action similar to that of virido-bufagin. Its minimal emetic dose in pigeons is 0.2 mgm., that in cats 0.15 mgm., and the average fatal dose in cats 0.27 mgm. per kilogram.

d. Virido-bufotenine A, in the form of a flavianate, C₁₂H₁₈O₂N₂.-C₁₀H₆O₈N₂S, which was isolated from our 1930 lot of secretion. It has an average of 65 per cent of the pressor activity of cinobufotenine flavianate.

e. Virido-bufotenine B, in the form of a flavianate, C₁₂H₂₀O₃N₂.-C₁₀H₆O₈N₂S, which was isolated from our 1931 lot of secretion. It is peculiar that it should differ from virido-bufotenine A. The flavianate of virido-bufotenine B has only 4 per cent of the activity of cino-bufotenine flavianate. Both virido-bufotenines A and B increase the tone of heart contractions in frogs and stimulate isolated smooth muscle organs.

Virido-bufotenine B, in the form of a flavianate, has the same melting point and elementary composition, and produces almost quantitatively the same physiological effects as areno-bufotenine A. They are probably identical.