Episodic Secretion of Aldosterone in Primary Aldosteronism: Relationship to Cortisol

Abstract

SUMMARY Plasma aldosterone, plasma cortisol and plasma renin activity were determined at short time intervals in three supine patients suffering from primary aldosteronism. The patients were studied both under normal conditions and during suppression of ACTH secretion by dexamethasone. Though abnormally high levels were found, aldosterone was secreted episodically in each patient while plasma renin activity was uniformly undetectable. In each patient the secretory episodes of aldosterone were paralleled by those of cortisol indicating that physiological variations in ACTH secretion markedly altered the secretion of aldosterone. The assumption that ACTH played an important role in the regulation of aldosterone secretion in primary aldosteronism was strengthened by the observation that, contrary to normal controls, dexamethasone produced a significant decrease in plasma aldosterone concentrations and that during suppression of ACTH secretion no secretory episodes of aldosterone were observed.

Chronobiology of Blood Pressure

“…PRA, which is measured in vitro by radioimmunassay of AI, is frequently used as an index of plasma All. In normal subjects, PRA shows a curve with acrophase between 04.00 and 08.00 h and the lowest values about 16.00 h [17], This has been documented by several laboratories in nor mal and hypertensive subjects [31.39,55], In patients with primary aldosteronism, in whom the values for PRA are suppressed, frequently to nondetectable concentrations, the circadian curve for plasma aldosterone is very similar to that of plasma cortisol [57], an indication that changes in aldosterone secretion probably depend upon changes in ACTH. Since in most cases the blood pressure curve is reduced in both amplitude and mesor after removal of the aldosterone-producing tumor, the curve of blood pressure is most likely influenced by aldosterone.…”

“…Cardiac output was not measured in this study. Kent et al [33] and Vetter et al [57] studied patients with primary aldosteronism who ex hibited circadian curves for plasma aldosterone with acro phase from 02.00 to 06.00 h.…”

Localization of Aldosterone-Producing Adenoma: Venous Sampling in Primary Aldosteronism.

“…Therefore, we modified the adrenal venous sampling technique by measuring both aldosterone and cortisol concentrations to calculate the LAV A/C and (LAV A/C)/ (IVC A/C) ratios. These two ratios made it possible to localize APAs and to distinguish this disorder from essential hypertension, es- Kem et al(1976) and Vetter et al(1974) reported the episodic secretion of aldosterone and cortisol in patients with primary aldosteronism, which may affect the A/C ratio of venous blood samples. However, the effect may be slight, since the secretory episodes of aldosterone are paralleled by those of cortisol (Vetter et al, 1974).…”

“…These two ratios made it possible to localize APAs and to distinguish this disorder from essential hypertension, es- Kem et al(1976) and Vetter et al(1974) reported the episodic secretion of aldosterone and cortisol in patients with primary aldosteronism, which may affect the A/C ratio of venous blood samples. However, the effect may be slight, since the secretory episodes of aldosterone are paralleled by those of cortisol (Vetter et al, 1974). Dunnick et al(1979) evaluated the A/C ratio of samples from both adrenal veins with and without stimulation of steroid production by administering ACTH, but in only one case was ACTH administration needed for the localization of APA.…”

Aldosterone Regulation in Primary Aldosteronism: Differences between Adenoma and Bilateral Hyperplasia

“…Furthermore, aldosterone secretion behaves in an analogous manner in primary aldosteronism (Kem, Weinberger, Gomez-Sanchez, Kramer, Lerman, Furuyama & Nugent, 1973; Ganguly, Melada, Luetscher & Dowdy, 1973;Vetter, Berger, Armbuster, Siegenthaler, Werning & Vetter, 1974), where plasma renin activity appears chronically suppressed. After dexamethasone this clinical picture disappears, indicating that ACTH plays a predominant role in aldosterone regulation in this disease.…”