The Effect of Cortin in Asthenia. ∗

Abstract

We have studied the effect of cortin in the asthenia of many clinical conditions including Addison's disease. These findings have been compared with observations on normal individuals.

In asthenia there is increased susceptibility to fatigue although the dynamic power of the muscle may not decrease materially. Therefore the measurement of asthenia should test the threshold for fatigue rather than the strength of a single contraction. An ergometer can be successfully used to measure the fatigue threshold provided certain precautions are observed. We employed the ordinary type which uses the middle finger to lift a weight. A load is chosen which will cause definite fatigue in 3 to 5 minutes when lifted every 2 seconds. If too heavy the error due to variation from one test to another may be large. The intervals between tests are great enough to eliminate the practise factor. The base level for fatigue shows less variation in many asthenic individuals than in normals. In all subjects it is necessary to avoid unusual exercise as this may increase the threshold for fatigue by practise on the one hand or decrease it if the exercise is too strenuous on the other.

Four normal individuals have been tested at frequent intervals before and after the injection of cortin. Many others have been tested without the injections. Occasionally in normals, the day to day variation is so great that it is almost impossible to obtain a consistent base level for fatigue. All normals showed an increase of 20 to 50% in the power to do work before fatigue developed, within 1 to 4 days after cortin was begun. The high point came several days after cortin was started, often after the latter had been discontinued.