A, Characterization of Cre recombinase expression in adult PTM-ARKO seminal vesicles. Approximately 50% of male PTM-ARKOs were Cre positive, identified by the presence of a band at 100 bp. Control littermates were negative for Cre but were positive for the internal control gene. B, Deletion of AR in the adult SV was determined using RT-PCR spanning exon 2. Only the larger 765-bp WT band was seen in control SVs, whereas the smaller 613-bp KO band was seen in ARKO testes. Both bands were identified in PTM-ARKO SVs, showing deletion of AR in a proportion of cells. C, Immunohistochemistry for Cre recombinase (green) and SMA (blue) showed that Cre recombinase was expressed selectively (arrow) in the smooth muscle cells of the SVs but not in any other SV cell types or smooth muscle cells in control SVs (*). Note that the smooth muscle layer appears narrower in the PTM-ARKO than controls. D, GFP [expression of which is also driven by the MH promoter in this mouse (47)] was expressed in the smooth muscle cells in PTM-ARKO SVs at d 100 (*) but not in the outer stromal cell layer (arrow); GFP was not detected in any cells in control SVs. Scale bars, 50 μm. E, In contrast, AR was expressed in the smooth muscle cells of control SV (arrowhead) but not PTM-ARKO SV smooth muscle cells (*); AR continued to be expressed in the epithelial and outer stromal cells (arrow) in the PTM-ARKO SV. Scale bars, 25 μm.