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

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

Wieland's bufotalin does not appear to occur in the secretion or skin of Bufo bufo bufo (B. vulgaris).

The three chief principles we isolated are:

(a) Cholesterol which is admixed with ergosterol in the proportion of 4.7 parts per thousand, as proved spectrographically.

(b) Vulgaro-bufotoxin, C₃₈H₆₀O₁₁N₄, which has a digitalis-like action, as shown by the myocardiogram, electrocardiogram, and the emetic action. The minimal emetic dose in pigeons is 0.2, that in cats 0.125, and the average fatal dose in 10 cats is 0.3 mgm. per kilogram. Its cardiac effect does not seem to be persistent. It has a pressor action due to constriction of blood vessels, and a stimulating action on the isolated intestines and uteri.

(c) Vulgaro-bufotenine, in the form of a flavianate, C₁₂H₁₈O₂N₂·-C₁₀H₆O₈N₂S, which contains an indole ring. It increases the tone of cardiac contractions in frogs as illustrated by perfusion, and stimulates the isolated intestines and uterus in dilute solutions, with prompt recovery. It raises the blood pressure in pithed cats with small doses (0.2 to 0.25 mgm.). Its pressor activity is on an average 58 per cent that of cino-bufotenine.