Fig. 2.

Effect of naringin on membrane voltage, CYP11B2 mRNA expression, and aldosterone production. Confluent cells were serum deprived in DMEM-F12 containing 0.1% cosmic calf serum for 24 h. Pretreatments with or without naringin for 30 min were performed for each experiment before adding secretagogue. A, HAC15 cells were incubated in HEPES buffer with 3 μm DiSBAC₂(3) and no secretagogue or A-II (10 nm) for 5 min. Fluorescence was detected by a plate reader. Results were expressed as fold change vs. control cells. *, P < 0.05 comparison between with and without naringin after A-II stimulation, n = 4. †, P < 0.01 comparison with the respective control, n = 4. B, Cells were incubated with no secretagogue or with A-II (10 nm) and without and with naringin for 6 h, and aldosterone was measured in the media. *, P < 0.05 comparison between with and without naringin after A-II stimulation, n = 4. †, P < 0.01 comparison with the respective control, n = 4. C, After 3 h incubation with no secretagogue or A-II (10 nm) and without and with naringin, cells were harvested for RNA extraction, and real-time RT-PCR was performed. Results were normalized by GAPDH mRNA expression and expressed as fold change vs. control. *, P < 0.05 comparison between with and without naringin after A-II stimulation, n = 4. †, P < 0.01 comparison with the respective control, n = 4.