The effects of canrenoate K on corticosteroid biosynthesis in nephrectomized dogs

Spontaneous remission of idiopathic aldosteronism after long-term treatment with spironolactone: results from the German Conn's Registry

CONTEXT

Primary aldosteronism (PA) is mainly caused by aldosterone-producing adenoma and idiopathic bilateral adrenal hyperplasia (IHA). Recently, spontaneous resolution of IHA has been described.

OBJECTIVE

We aimed to determine the frequency of spontaneous remission of PA during long-term treatment with mineralocorticoid receptor (MR) antagonists.

DESIGN, SETTING AND PATIENTS

Thirty-seven patients of the Munich PA registry with IHA treated by MR antagonists were investigated. The patients were identified retrospectively by chart review and prospectively assessed by clinical and biochemical means.

MAIN OUTCOME MEASURES

Complete remission of IHA was defined as normal aldosterone to renin ratio (ARR), normal suppression test and normalization of hypokalaemia in the presence of normal blood pressure. Partial remission was defined as normalization of normal ARR, normal suppression test and normalization of hypokalaemia in the presence of persistent hypertension.

RESULTS

The mean period of MR antagonist treatment was 5·8 ± 0·7 years in the patients. We identified two of 37 (5·4%) patients with spontaneous remission: one with complete remission and one with partial remission.

CONCLUSION

Remission of IHA in PA may occur in some patients after long-term mineralocorticoid antagonist treatment.

Contrasting effects of eplerenone and spironolactone on adrenal cell steroidogenesis

Spironolactone and eplerenone are widely used as mineralocorticoid antagonists. Spironolactone has several nonspecific actions including inhibition of androgen receptor and steroid hormone biosynthesis. While studies have shown that eplerenone does not exhibit nonspecific actions on androgen receptor, its effects on steroid hormone production have not been reported. Herein, the effects of eplerenone (0.1-30 microM) and spironolactone (0.1-30 microM) on steroid production were examined in human adrenocortical H295R cells. Spironolactone inhibited basal production of cortisol (91%) and aldosterone (53%). Treatment of H295R cells with angiotensin II (Ang II) for 24 h increased aldosterone production by 11-fold. Spironolactone inhibited Ang II stimulation of aldosterone production by 80%. Addition of pregnenolone increased aldosterone (9-fold) and cortisol (3-fold) production. Spironolactone inhibited pregnenolone metabolism to aldosterone (67%) and cortisol (74%). The inhibitory effects of spironolactone occurred at concentrations far higher than those needed to block mineralocorticoid receptor, suggesting an action directly on the enzymes involved in steroid production. In contrast, eplerenone did not inhibit basal, Ang II, forskolin, pregnenolone-stimulated cortisol, or aldosterone production. Together, these data demonstrate that opposed to spironolactone, pharmacologic concentrations of eplerenone do not inhibit adrenal cell aldosterone or cortisol production.