Studies Of Immunohistochemistry And In Site Hybridization On GnRH And Its Relative Hormones In The Body Of Two Kinds Of Siluriformes Fish In Sexually Immature And Mature Stage

An investigation using immunocytochemical technique of the strept avidin biotin-peroxidase complex(SABC) method was made in order to examine the identification and localization of the endocrine cells of brain, pituitary, gonad and digestive system in two kinds of siluriformes fish:Yellow catfish( Pelteobagrus fulvidraco) and Oriental sheatfish(Silurus asotus). Eight antiseras of rabbit anti-gonadotropin-releasing hormone (GnRH), anti-gonadotropin-releasing hormone receptor (GnRHR), anti-5-Hydroxytryptamine (5-HT), anti-5-Hydroxytryptamine receptor (5-HTR), anti-somatostatin (Som), anti-Growth hormone (GH) and mouse anti-luteinizing hormone(LH) and anti-follicle stimuling hormone(FSH) were used. The result showed that: in sexually immature and mature stage, positive reactions with antiseras against GnRH, GnRHR, 5-HT, 5-HTR were found in brain , pituitary, gonad and digestive tract; positive reactions with FSH, LH were found in brain , pituitary, gonad; positive reactions with GH were found in brain, pituitary, gonad pancreas and digestive tract in P. fulvidraco; and in S. asotus positive reactions with GH were found only in pituitary. The number of immunoreactive cells and positive reactions of GnRH, GnRHR, LH and FSH in the hypothalamus, pituitary and gonad in the pituitary of two fish were significantly higher in sexually mature stage than in immature stage and no distinct changes were observed in other parts in the body. The positive reactions of Som, GH, 5-HT and 5-HTR in the ovary in the hypothalamus and ovary hadn' t been detected differences in other parts. On the basic of immunocytochemical, in site hybridization was used in order to in examine the identification and localization of the GnRH-mRNA cells in the body of two fish. The result was that: localization and expression of GnRH-mRNA was found in brain, pancreatic, gonad and digestive tract; the positive reaction was significantly higher in sexually mature stage than in immature stage. So we thought that GnRH, GnRHR, LH and FSH play an important pole in themodification of gonadal development of P. fulvidraco and S. asotus. Those results provided morphological basis and molecular basic for the research of brain-pituitary-gonadal axis and neuro-endocrine system.