Figure 8.
The activities of the steroidogenic enzymes 3β-HSD (A), P450c17 (B), and 17β-HSD (C). Leydig cells were isolated from 4- and 24-month-old rats that were treated with either BSO or vehicle (PBS) for 7 d. The cells were incubated in vitro with the substrate for 3β-HSD (pregnenolone, 12.5 μm), P450c17 (progesterone, 12.5 μm), or 17β-HSD (androstenedione, 6.25 μm) for 2 h. The Δ4–3-ketosteroid products of each enzyme were quantified by HPLC. The data are expressed as mean ± sem of six animals per group. *, Significantly different from cells isolated from age-matched control animals at P < 0.05.