Quantitative experiments on the liberation of epinephrin from the adrenals after section of their nerves, with special reference to the question whether epinephrin is indispensable for the organism

Abstract

1. We showed in a previous paper by the blood pressure and eye reactions that after section of the nerve supply of the adrenal no demonstrable liberation of epinephrin was present in cats as long as five weeks after the nerve section. 2. As it is easier to detect very small concentrations of epinephrin by the rabbit intestine and uterus segments, we have made a series of experiments (on 7 cats) in which these tests were used to supplement the eye reactions. In all the animals one adrenal was excised and the nerves of the other cut. In a cat tested two weeks after the operation, it was shown that the adrenal blood serum could not have contained I : 300,000,000, or the blood I : 400,000,000, of epinephrin; and that the rate of liberation of epinephrin could not have been at most O.OOOOOI mgm. per minute for one adrenal. In another cat three weeks after the operation the serum of the adrenal blood was proved to contain less than I : 400,000,000, and the blood less than I : 700,000,000 epinephrin. The output of epinephrin per minute could not have been as much as o.oooooog mgm. per minute, for one adrenal. The segments used for the tests in these experiments were extremely sensitive, and the limits of adrenalin concentrations which could be detected with certainty were carefully determined. The eye reactions were negative. In these two cats the rate of liberation of epinephrin, if any liberation whatever was going on, must have been several hundred times less than the rate in normal animals under the same experimental conditions. It is scarcely necessary to point out that experiments yielding completely negative results indicating the absence of epinephrin with very sensitive test objects are much more important for the questions studied than experiments in which small amounts of epinephrin can still be detected.