THE PHYSIOLOGICAL ACTION OF THE PRINCIPLES ISOLATED FROM THE SECRETION OF THE JAMAICAN TOAD (BUFO MARINUS)

¹ From the Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana

From the parotid secretion of the Jamaican toad, Bufo marinus, the following principles have been isolated and studied pharmacologically:

A. Cholesterol. Spectrographic examination showed the presence of ergosterol in the proportion of 1.3 parts per thousand.

B. Marino-bufagin, C₂₈H₃₆O₆ or C₂₄H₃₂O₅, having a digitalis-like action. The minimal emetic dose in pigeons is 0.375 mgm., that in cats 0.3 mgm., and the average fatal dose in cats 0.57 mgm. per kilogram.

C. Marino-bufotoxin, C₄₂H₆₂O₁₁N₄ or C₃₈H₅₈O₁₀N₄, also having a digitalis-like action. The minimal emetic dose in pigeons is 0.2 mgm., that in cats 0.125 mgm., and the average fatal dose in 18 cats is 0.43 mgm. per kilogram. Both marino-bufagin and -bufotoxin have a protracted pressor action and a stimulating effect upon the isolated smooth muscle organs.

D. Marino-bufotenine in the form of a flavianate, C₁₂H₁₄O₂N₂·-C₁₀H₆O₈N₂S. It is an indole derivative. It produces contractions of isolated guinea pigs' virgin uteri, but, unlike other active bufotenines, it has practically no pressor action in pithed cats, has no effect on isolated rabbits' intestines, and causes no marked increase in the tone of the frog's heart.

E. Epinephrine. By the blood pressure method in pithed cats, it has been estimated that the dried secretion contains an average of 5.3 per cent of epinephrine, and that each toad has an average of 41.19 mgm. in its pair of parotid glands.

We have made a similar chemical study of the back of the toad's skin, excluding the parotid glands. It has been found that both cholesterol and marino-bufotoxin can be obtained in crystalline form, but no evidence for the occurrence of marino-bufagin and epinephrine is demonstrable. Apparently the wart secretion does not contain all the constituents of the parotid secretion.