title: Characterization of tilapia (Oreochromis niloticus) gonadotropins by modeling and immunoneutralization.
abstract: In fish, both follicle-stimulating hormone (FSH) and luteinizing hormone (LH) play important roles in reproduction. Here we explored the structure and differential specificity of tilapia (t) gonadotropins (GTHs) to delineate their physiological relevance and the nature of their regulation. We generated structural models of tGTHs and GTH receptors (R) that enabled us to better understand the hormone-receptor interacting region. In tilapia, FSH release is under the control of the hypothalamic decapeptide GnRH, an effect that was abolished by specific bioneutralizing antisera [anti-recombinant (r) tFSHβ]. These antisera also reduced the basal secretion and delayed GnRH-stimulated production of 11-ketotestosterone (11KT), and dramatically reduced LH levels. Immunoneutralization of tLH using anti-rtLHβ significantly reduced its GnRH-stimulated levels. Basal 11KT and FSH levels were also reduced. Taken together, these results suggest a feedback mechanism between FSH and LH release in tilapia.
authors: The Robert H. Smith Faculty of Agriculture, Food and Environment, Department of Animal Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
authors: Joseph
authors: J
authors: Aizen
authors: The Robert H. Smith Faculty of Agriculture, Food and Environment, The Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
authors: Noga
authors: N
authors: Kowalsman
authors: The Robert H. Smith Faculty of Agriculture, Food and Environment, The Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, Rehovot 76100, Israel; The Fritz Haber Research Center for Molecular Dynamics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
authors: Masha Y
authors: MY
authors: Niv
authors: The Robert H. Smith Faculty of Agriculture, Food and Environment, Department of Animal Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel. Electronic address: berta.sivan@mail.huji.ac.il.
authors: Berta
authors: B
authors: Levavi-Sivan
mesh_terms: D000818:Animals; D000906:Antibodies / Q000494:pharmacology*; D023681:Cichlids / Q000254:growth & development / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D025461:Feedback, Physiological / Q000187:drug effects; D005640:Follicle Stimulating Hormone / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D007986:Luteinizing Hormone / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D008958:Models, Molecular; D011487:Protein Conformation; D012098:Reproduction / Q000502:physiology; D013739:Testosterone / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D000906:Antibodies; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; C003600:11-ketotestosterone
keywords: 11-ketotestosterone; FSH; GnRH; Gonadotropin receptor; LH