[1] Boston Univ, Sch Med, Dept Biochem, Boston, MA 02118 USA
[2] Boston Univ, Sch Med, Div Urol, Boston, MA 02118 USA
[3] Brown Univ, Dept Family Med & Urol, Warren Albert Sch Med, Providence, RI 02906 USA
[4] Harvard Univ, Beth Israel Deaconess Med Ctr, Sch Med, Div Urol, Boston, MA 02215 USA
[5] Univ Clin Muenster, Ctr Reprod Med & Androl Clin Androl, Munster, Germany