Somatostatin in lungfish kidney: an immunohistochemical, autoradiographical and in situ hybridisation study

The localisation of somatostatin-14 (SST-14) was examined immunohistochemically using the antibody Ab-SST-14 in the kidney of the African lungfish Protopterus annectens. Immunoreactive cells were present in the proximal tubules. In situ hybridisation, using an oligonucleotide probe complementary to mRNA for SST-14 and labeled at the 3'-end with alpha-35S, showed SST-14 mRNA distributed in cells with the same localisation as seen for SST-14 immunoreactive cells. Binding sites for SST-14 were identified with autoradiography using 125I SST-14. Binding sites were concentrated on cells of the proximal tubules. It is suggested that SST-14 may be synthesised in the lungfish mesonephros.