Fig. 6

Five μm thick paraffin sections from salmon testis, showing the detection of amh mRNA in Sertoli cells. a In immature testis tissue, the cytoplasmic extensions of most Sertoli cells are strongly positive for amh mRNA (white arrows), enveloping unlabeled type A spermatogonia. b In early maturing testes containing type A and type B spermatogonia, amh mRNA is still detectable in the cytoplasm of Sertoli cells, some cells showing a strong staining (white arrows) that, however, no longer extends into the cytoplasmic extensions, while many Sertoli cells show a weak staining (black arrows), often restricted to the perinuclear area, or no staining at all. Please refer to Additional file 2: Figure S2 for a sense control staining. Black bars correspond to 50 μm length