Regulation of aldosterone secretion by mineralocorticoid receptor–mediated signaling

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   Figure 1

   Western blot analyses showing expression of MR, GR, CYP11B2 and CYP11B1 in zona glomerulosa cells obtained from rats maintained on low-salt (LS) or high-salt (HS) diets. HS diet reduced CYP11B2 levels but increased CYP11B1 expression. Representative Western blots are shown above each graph. n = 9 per group (Controls are the lower panels). **P < 0.01; ***P < 0.001.
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   Figure 2

   Western blot analyses showing the expression of MR, GR, CYP11B2 and CYP11B1 in zona fasciculata/reticularis cells obtained from rats maintained on low-salt (LS) or high-salt (HS) diets. CYP11B1 levels are not significantly affected by dietary salt. CYP11B2 was non-detectable in these cells. Representative Western blots are shown above each graph (Controls are the lower panels). n = 9 per group. *P < 0.05.
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   Figure 3

   Effect of activation of MR by fludrocortisone (FLUDRO) on basal (left panel) and stimulated (right panel) aldosterone release by zona glomerulosa cells from low salt-treated rats. Results are means ± s.e.m. (n = 8) and are expressed as percentage of secretion with controls set at 100%. *P < 0.05, **P < 0.001.
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   Figure 4

   Effect of MR inhibition on baseline and ANGII-stimulated aldosterone secretion by isolated zona glomerulosa cells from rats fed a low-salt diet. Results are means ± s.e.m. (n = 22) and are expressed as percentage of secretion with controls set at 100%. *P < 0.05, **P < 0.01, ***P < 0.0001.
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   Figure 5

   Corticosterone (CORT) secretion in isolated zona glomerulosa cells from rats on a low-salt diet with FLUDRO (A, B with n = 8) and canrenoic acid (C, D with n = 22) treatment. Results are means ± s.e.m. and are expressed as percentage of secretion with controls set at 100%. *P < 0.05, **P < 0.005.
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   Figure 6

   Modulation of MR function in zona glomerulosa cells from rats on a high-salt diet. Effect of FLUDRO (A, B with n = 4) and CAN (C, D with n = 6) on aldosterone secretion. Results are means ± s.e.m. and are expressed as percentage of secretion with controls set at 100%. *P < 0.005, **P < 0.001.
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   Figure 7

   Effect of modifying GR activity on aldosterone secretion in zona glomerulosa cells from low salt fed rats. Cells were incubated with DEX. a GR agonist (A, B) and RU486, a GR antagonist (C, D). Results are means ± s.e.m. with n = 6 and are expressed as percentage of secretion with controls set at 100%. *P < 0.005.
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   Figure 8

   Inhibition of stimulated corticosterone secretion by DEX in zona fasciculata/reticularis cells from low salt fed rats. Results are means ± s.e.m. (n = 8) and are expressed as percentage of secretion with controls set at 100%. *P < 0.05, **P < 0.0005.
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   Figure 9

   RU486 treatment stimulates corticosterone production in ACTH-stimulated zona fasciculata/reticularis cells from rats fed a low-salt diet. Results show means ± s.e.m. (n = 8) and are expressed as percentage of secretion with controls set at 100%. *P < 0.05, **P < 0.005.
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    Figure 10

    Effect of MR activation on corticosterone from low salt (LS, top panels) and high salt (HS, bottom panels) zona fasciculata/reticularis cells. Results are means ± s.e.m. (n = 6) and are expressed as percentage of secretion with controls set at 100%. *P < 0.05, **P < 0.005.
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    Figure 11

    MR blockade with canrenoate did not alter corticosterone secretion in basal and ACTH-stimulated zona fasciculata/reticularis cells on low salt. Results are means ± s.e.m. (n = 6) and are expressed as percentage of secretion with controls set at 100%.

• © 2017 Society for Endocrinology