Figure 1.

Mineralocorticoid receptor (MR) staining in isolated fragments of the aldosterone-sensitive distal nephron (ASDN) from control (A and B) and MR knockout (KO) mice (C and D). In the control mouse, the MR antibody mainly caused nuclear staining (red) in the connecting tubule (CNT)/cortical collecting duct (CCD) as well as in the late distal convoluted tubule (DCT2)/CNT. This nuclear staining was essentially absent in the MR KO mouse. Areas indicated in A and C are shown on an enlarged scale in B and D, respectively. DAPI costaining (blue) confirmed the nuclear localization of MR staining in the control mouse and its absence in the MR KO mouse. E: summary data from similar experiments as shown in A– D. The percentage of MR-positive nuclei in tubules isolated from control (N = 7) and MR KO mice (N = 8) was determined in several ASDN fragments from each animal. Each point corresponds to an individual tubular fragment. Data points connected by a vertical line are from the same animal identified by a number. Median and quartiles are shown. Mouse 1 in the control group and mouse 4 in the MR KO group were females; all other animals were males. The age of the animals ranged from 45 to 104 days in the control group and from 53 to 102 days in the MR KO group.