Figure 3.

SF1 stimulates steroidogenic enzyme activity in prostate epithelial cells. A, Classic (Δ5 [left] and Δ4 [middle]) and alternative pathways for sex steroid production are shown. Each steroidogenic enzyme except SRD5A1, SRD5A2, and RDH5 is regulated by SF1 (★, known SF1 target genes; ★?, genes that have SF1 binding sites within their proximal promoter but have not been directly tested for SF1 regulation). To optimize steroid detection, cells were incubated in medium spiked with an upstream steroid precursor, pregnenolone (shaded box). Unshaded boxes denote steroids that were subsequently measured by LC/MS-MS from cell culture media (nanograms per milliliter of medium). B, Presence of SF1 exerted a significant effect on progesterone production (*, P ≤ .05, Student t test, one-tailed, equal variance); low levels of DHEA and DHT were detected (note scale difference), which followed the same trend as progesterone in the absence or presence of SF1. White bars, BPH-1–mCherry; dark gray bars, BPH-1–mCherry-SF1; light gray bars, BCaPT10-shNEG; black bars, BCaPT10-shSF1. Androstanediol concentrations were below the limits of detection.