Figure 3

Dose response effect of steroids on DOC-incubated release of aldosterone by PCMV-CYP11B2- or chimeric PCMV-CYP11B1/B2-transfected HEK-293 cells. The mean aldosterone production by ASCE was 13.6 μM/24 h and by ASWT was 15 μM/24 h, when incubated with 1.5 μM of DOC. A) Inhibition of ASCE by progesterone was statistically significant from 5 μM and for ASWT from 2.5 μM (+ and *, p > 0.01). B) Dose response curve for aldosterone production by ASCE and ASWT (μM/24 h) versus the logarithm of the progesterone concentration. A calculated IC50 value of 3.907 μM for ASCE and 2.240 μM for ASWT was obtained. C) Estradiol shows no inhibitory activity on the ASCE or ASWT enzymes in the range of concentrations probed. D) Ketoconazole inhibited both enzymes by 90% at all concentrations probed (p < 0.001). E) Cell viability of HEK-293 incubated with increasing doses of progesterone and estradiol (progesterone and estradiol or ketoconazole) (0.8-50 μM). Data are expressed as the mean +/− S.E.M. of 4 independent trials.