Fig. 3. Histological analysis of the interrenal primordium at 3 dpf. (A-C) Interrenal primordium (irp) is located ventral to the notochord (n) and dorsal to the gut (g). (A,B) Hematoxylin and Eosin staining and (C) hybridization of the cross sections of interrenal primordium with ff1b. (B,C) Higher magnification of A. The blue arrowhead indicates the capsule like structure. (D) The interrenal primordial cells have many mitochondria in their cytoplasm. (E) Higher magnification of the dashed square in D. g, gut; m, mitochondria; n, notochord; Nu, nucleus; p, pigment; pt, pronephric duct. Scale bar: 1.1 µm (D), 0.25 µm (E).