Figure 2.

Baseline LH and FSH levels in brothers (black bars) and control men (open bars) were similar. LH and FSH responses to GnRH agonist stimulation were higher in brothers (*P = 0.02 for LH; **P = 0.004 for FSH). Lower Δ17Prog/ΔAD (^†P = 0.003) in brothers during the GnRH agonist stimulation test suggests that they have increased gonadal 17,20-lyase activity compared with control men. Higher ΔAD/ΔT in brothers during the GnRH agonist stimulation test (^‡P = 0.005) suggests that this group also has reduced 17β-HSD activity in comparison to control men. Comparison of baseline and stimulated FSH levels were made by Wilcoxon rank-sum tests. All other comparisons were made by t-tests (LH, luteinizing hormone; FSH, follicle-stimulating hormone; 17Prog, 17-hydroxyprogesterone; AD, androstenedione; T, testosterone).