Katsuo Nakajima

A simple method measuring plasma aldosterone by radioimmunoassay without extraction

: A radioimmunoassay method was developed to measure plasma aldosterone levels. Antibody was produced in rabbits by injecting aldosterone oxime coupled with bovine gamma-globulin once a month. Plasma aldosterone was measured simultaneously by two methods: the direct method without extraction and a method using paper chromatography. 125I-aldosterone was used in the first method and 3H-aldosterone in the second. The antibody had a high specificity adequate to show zero water blank in the first method. Adequate precision, accuracy and sensitivity were obtained in a direct method using 125I-aldosterone. Plasma aldosterone levels were 7.1+/-3.0ng/100ml (Mean +/-SD) in normal subjects and slightly higher after injecting ACTH-Z. The correlative coefficient between the first and the second method was significantly high (r=0.970, P less than 0.001, n=37). Plasma aldosterone was high (34.3+/-14.1ng/100ml, n=7) in primary aldosteronism, slightly high (14.2+/-2.6ng/100ml) in secondary aldosteronism, normal in Cushings syndrome (10ng/100ml) and low in Addisons disease (1ng/100ml), hypopituitarism (1ng/100ml) and pseudoaldosteronism (2ng/100ml). From these results, it is concluded that the direct method without extraction was a very useful and reliable method for measuring plasma aldosterone. It was superior in simplicity and there is no need to use a liquid scintillation counter.

Microdetermination of Corticosteroids in Adrenocortical Zones in Various Adrenal Diseases

Since the relationship between steroidogenic activity and morphological differentiation is not necessarily clear in the human adrenal cortex, aldosterone (Al), cortisol (F) and corticosterone (b) from the adrenal tissues cut into four small pieces (capsule and glomerulosa, outer fascicular, inner fascicular, and reticular zones) on a cryostat immediately after their removal at surgery were estimated by radioimmunoassay in 15 patients with adrenal diseases (8 primary aldosteronism, 1 idiopathic aldosteronism, 4 Cushings syndrome and 2 pheochromocytoma) and 8 control subjects with other diseases. A larger amount of Al was contained in the outer fascicular zone than in other zones in control subjects. Al showed a high value of 0.16 approximately 7.40 ng/mg tissue in adenomas of primary aldosteronism and a low value of 0 approximately 0.25 ng/mg tissue in adenomas of Cushings syndrome. A high value of Al was detected in idiopathic aldosteronism but not in the remaining adrenal of primary aldosteronism. In Cushings syndrome, F showed a high value of 2.58 approximately 12.3 ng/mg tissue in adenoma and a relatively low level of 0.77 ng/mg tissue in carcinoma. A larger amount of F and B was found in the inner fascicular zone than in other zones in the control subjects. These results indicate that the corticosteroid content in each adrenal zone correlates with the morphological findings.

Comparative Study of Diagnosis for Location of Adrenal Adenoma in Patients with Primary Aldosteronism

Four methods; retroperitoneal air insufflation study, adrenal phlebography, adrenal scintiscan and estimation of plasma aldosterone in adrenal or renal veins, were compared to determine the diagnostic value for the location of adrenal adenoma in 27 patients with primary aldosteronism and one with idiopathic aldosteronism. The location of adrenal adenoma could be certainly determined, in 12 of 27 patients with primary aldosteronism by retroperitoneal air insufflation study, in 7 of 22 by adrenal phlebography, in 18 of 23 by estimation of aldosterone in adrenal or renal vein blood, and in 19 of 27 by adrenal scintiscan. From these results, it is concluded that firstly adrenal scintiscan with 131I-cholesterol and then adrenal phlebography and estimation of aldosterone in adrenal and renal vein blood combined with retroperitoneal air insufflation study should be performed for determination of location of adrenal adenoma in primary aldosteronism.