Clinical studies on adrenocortical function, with emphasis on the reaction of serum 17-hydroxycorticosteroids to ACTH. 1. Evaluation of intramuscular administration of ACTH-Z for testing the adrenocrotical reserve function

Abstract

The current method of estimating the change of plasma 17-OHCS level following intravenous administration of ACTH is the most specific and quantitative method for testing the reserve function of the adrenal cortex, but it has the defect of causing a heavy physical burden on the patient. In consideration of such an inconvenience, the present author undertook to study the utility of intramuscular administration of long-acting ACTH-Z, instead of the intravenous ACTH test for testing the adrenocortical reserue function. The results, in summary, were as follows : 1) In 6 normal controls, the eosinophil count after intramuscular administration of ACTH-Z 20 units fell to the lowest level in 9-12 hrs, the rate of decrease amounting to -78.8% or more.2) In 10 normal controls, the mean eosinophil count following intramuscular administration of ACTH-Z 40 units fell by -87.9% in 8 hrs. In 9 other normal controls, the mean drop of the count after 6 hours intravenous infusion of ACTH 25 units was -84.2%, so that no significant difference was observed between the results of intramuscular and intravenous administration.3) In 8 normal subjects, the mean of control plasma 17-OHCS levels stood at 12.8γ/dl, and at 24.8γ/dl and 38.6γ/dl 4 hours and 8 hours after intramuscular administration of ACTH-Z 40 units. In 10 normal controls, the plasma 17-OHCS level was 12.4γ/dl, after 3 and 6 hours of intravenous ACTH 25 units infusion, the plasma levels were 25.9γ/dl and 34.9γ/dl. Thus, the value, 8 hours after the intramuscular administration was somewhat higher than the 6 hours intravenous infusion, but the rising range after both methods proved nearly the same. In 2 subjects, both subjected to both the tests, similar results were obtained.The above findings showed that the method of estimating the rate of decrease of eosinophil count and the change of plasma 17-OHCS level 8 hours after intramuscular administration of ACTH-Z 40 units is clinically serviceable for testing the reserve function of the adrenal cortex, as faithfully as the cumbersome 6 hour-intravenous ACTH infusion method currently in practice.4) In testing the adrenocortical reserve function in some adrenal disorders by this new method or a standard ACTH test, it was found that : a) In 2 cases of suspected Addison's disease, complaining of weakness, loss of weight and hyperpigmentation, the adrenocortical reserve capacity was subnormal.b) In a case of acanthosis nigricans accompanying gastric cancer, the response to ACTH administration was mildly diminished, and at autopsy, the adrenal metastasis of cancer was found.c) In 4 cases of primary aldosteronism, some showed mild decrease but the others showed no change in the adrenocortical reserve capacity, no definite tendency being perceptible.d) In a case of malignant pheochromocytoma, the plasma 17-OHCS level and the urinary 17- OHCS and the 17-KS excretion showed abnormally high values, revealing a hyperfunction but a diminished reserve capacity of the adrenal cortex.