Males were castrated as previously described [41 (link)]. After castration, silastic hormone pellets containing 12.5 mg testosterone (Steraloids, Newport, RI) were surgically implanted to induce prostatic regeneration. A 1 cm implant maintains host testoster-one levels at 5.3 T 0.5 ng/ml (18.2 nM) which is similar to eugonadal adult human males [43 (link)]. Animals were age-matched across conditions. All procedures were done in accordance with Institutional Animal Care and Use Committee (IACUC) guidelines, all efforts were made to minimize suffering. Prostatic regression and regeneration each took place over 3 weeks.