Next, to address putative on-target side effects, we tested the effect of repeated administration of mPD5 (s.c., 10 μmol/kg, once daily for 14 days) versus vehicle on male fertility (Figure 6, C–F, and Supplemental Figure 8, B and C), since complete loss of PICK1 is known to cause male infertility (50). The gene discussed is PICK1; the disease is male infertility.