Table 1.

MR fragments and RBC Aldo concentrations after in vitro treatment. Isolated RBC from 4 healthy controls (HC) at 20% hematocrit were incubated at 37°C for 1 h in absence (C) or presence of 2, 5 and 10 nM aldosterone (Aldo), 1 µM canrenone (Can), 5 µM cortisol (Cort) and 5 nM Aldo plus 1 µM Can (Aldo 5 nM+Can) or 5 nM Aldo plus 5 µM Cort (Aldo 5 nM+Cort). Diluted cytosol, obtained as described in Methods, was separately analysed for MR fragments and Aldo content. MR fragments: diluted cytosol (300 µl) was loaded in a linear glycerol gradient and centrifuged for 18 hours at 100 000×g. Fractions 3 and 4 (200 μL each) from top were analysed by Western blotting in non-reducing conditions and immune-detected with anti-MR antibody. RBC [Aldo]: diluted cytosol (100 µl) was analysed by RIA as described in Methods

In vitro assay	MR fragments in fraction 3-4%	RBC [Aldo] ng/dl
C	100±3	5.8±0.2
Aldo 2 nM	130±8a	11.6±0.5a
Aldo 5 nM	145±7a	30.7±2.5a
Aldo 10 nM	172±5a	67.1±3.2a
Can	104±1b	5.7±0.2b
Aldo 5 nM+Can	103±3c	6.2±0.3c
Cort	102±6b	5.9±0.3b
Aldo 5 nM+Cort	103±3c	6.3±0.3c

Data are the mean ± SD of four separate determinations. Statistical analysis was performed using ANOVA followed by Tukey-Kramer post hoc test.

^a p<0.0001, comparison versus C;

^b p not significant, comparison versus C;

^c p<0.0001, comparison versus Aldo 5 nM.