Abstract: Abstract: Objective To investigate the effects of aldosterone on the expression of endothelin (ET) in cultured neonatal rat cardiac fibroblasts. Methods Cardiac fibroblasts were isolated by trypsin digestion method. ET-1 concentration in conditioned medium was measured by radioimmunoassay, intracellular ET-1 level was evaluated by flow cytometry, and the expression of preproendothelin-1 (ppET-1) was detected and quantified using quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) method. Results Aldosterone (10-9, 10-8, 10-7 mol/L) induced a dose-dependent changes in ppET-1 mRNA expression, as well as ET-1 synthesis and secretion in cardiac fibroblasts. Meanwhile, aldosterone (10-7 mol/L) time-related induced ppET-1 mRNA expression in cardiac fibroblasts, which began to increase in 2 h and attained the highest level in 4 h, thereafter decreased. The effects of aldosterone (10-7 mol/L) were significantly inhibited by the pre-incubation with spironolactone (10-6 mol/L). Conclusion These results showed that aldosterone increase the expression of ppET-1 mRNA, as well as ET-1 synthesis and secretion via mineralocorticoid receptor.

Key words: aldosterone, spironolactone, endothelin, cardiac fibroblasts