Studies On The Function Of The Reproductive Endocrine And Its Regulation-controlling Mechanism In Stone Flounder Kareius Bicoloratus

The gonad of fish is not only the tissue which can produce gametes, but also an important endocrine gland. The steroid hormone, produced by gonad, regulates the forming and release of GtH through feedback effect during the development and maturation of gonads in fish. Accordingly, changes are occurent in the pituitary cells and steroid hormone in plasma. In this research, the gonad, pituitary and sexual steroid hormone of stone flounder (Kareius bicoloratus) are studied by histological staining techniques, immunohistochemical and radioimmunoassay mehods. 1. Histological study on the development and annual change in the gonad of stone flounder There is a pair of triangular ovaries in stone flounder. The color of immature ovary is light yellow or rosiness and that of the mature one is maize or mahogany. The development of ovary can be divided into six stages and the oocytes be divided into five phases. It is difficult to differentiate the oogonium from spermatogonia; The yolk nuclear appears in phase 2 oogyte and vitellin starts to accumulate in phase 3 oogyte; There are two follicular cells in phase 4 oogyte; The nuclear deflexion and formation of embryo radicel occur in the telophase of phase 4 ovary; The nuclear disappears in phase 5 oogyte when the oogyte becomes dissociating. In the stage VI, vitellin granule starts to inosculate into big granule, and degenerate, be assimilated subsequently. The ovary, which gets to the stage II, can be easily dyed to deep blue. Great changs take place in the nucleolus, follicular cells and cell volume in different phases.The double testes of stone flounder is lobular type in appearance. The immature testis is filament, half clarity while the mature one is big velvet, milkiness in color. The development of testis can be devided into six stages and the development of male germ cells experience four cell-types, including spermatogonia, spermatocytes, spermatid and spermatozoa. Thereinto, the stage III testis includes all kinds of male germ cells; In the later of stage IV, the development of the...