Fig. 2.

Histological examination of fish. (A) The complete fish was fixed at 2 d after surgery. All sections were stained with H&E. The insets in a, b, e, and f are enlarged in the brackets of figures. The sham-operated fish appeared normal with no damage (a and b). The gonads were completely removed in gonadectomized fish (c and d). Sections of ectopic-transplanted fish showed that the gonads were completely removed from the normal location, and the transplanted gonads were located in the muscle (e and f). (Scale bars: 200 μm in a, b, c, and d; 0.5 mm in e and f; 20 μm in Insets in a, b, e, and f.) (B) Ectopic gonads were fixed at 50 d after operation, and all sections were stained with H&E. Male gonads were completely mature, and spermatozoa were observed (male). Mature eggs were not observed in ectopic female gonads (female), but ovarian follicles at the early vitellogenic stage were present. (Scale bars: 20 μm for males, 50 μm for females.)