THE PHYSIOLOGICAL ACTION OF THE PRINCIPLES ISOLATED FROM THE SECRETION OF THE JAPANESE TOAD (BUFO FORMOSUS)

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 Japanese toad, Bufo formosus, the following principles have been isolated and studied pharmacologically:

a. Cholesterol, which is admixed with very little or no ergosterol.

b. Gama-bufagin, C₂₇H₃₈O₆, which has a digitalis-like action. The minimal emetic dose in pigeons is 0.15 mgm., that in cats 0.07 mgm., and the average fatal dose in 10 etherized cats 0.1 mgm. per kilogram.

c. Gama-bufotoxin, C₄₁H₆₄O₁₁N₄, which also has a digitalis-like action. The minimal emetic dose in pigeons is 0.20 mgm., that in cats 0.175 mgm., and the average fatal dose in 10 etherized cats 0.38 mgm. per kilogram. Both gama-bufagin and gama-bufotoxin have a pressor action and stimulate isolated intestines and uteri.

d. Gama-bufotenine, in the form of a flavianate, C₁₂H₁₈0₂N₂.-C₁₀H₆O₈N₂S, which is an indole derivative. It has an average of 89 per cent of the pressor activity of cino-bufotenine flavianate. It increases the tone of cardiac contractions in frogs and stimulates isolated intestines and uteri.

Evidence has also been obtained, both chemically and physiologically, of the presence of epinephrine in the secretion.