Adult testes are positive control for in situ hybridization specificity. Testes hybridized with antisense configured probes for 3β-HSD (A and C), CYP11A1 (E and G), and StAR (I and K) show high levels of hybridization over cells patterned as Leydig cells in film images (A, E, and I) and emulsion dipped slides (C, G, and K). No hybridization is seen with sense configured probes (B, F, and J and D, H, and L). Scale bar (A), 1 mm (A, B, E, F, I, and J); scale bar (C), 100 µm (C, D, G, H, K, and L).