Characterization of tilapia (Oreochromis niloticus) gonadotropins by modeling and immunoneutralization

Joseph Aizen; Noga Kowalsman; Masha Y Niv; Berta Levavi-Sivan

doi:10.1016/j.ygcen.2014.05.028

Characterization of tilapia (Oreochromis niloticus) gonadotropins by modeling and immunoneutralization

Gen Comp Endocrinol. 2014 Oct 1:207:28-33. doi: 10.1016/j.ygcen.2014.05.028. Epub 2014 Jun 2.

Authors

Joseph Aizen¹, Noga Kowalsman², Masha Y Niv³, Berta Levavi-Sivan⁴

Affiliations

¹ The Robert H. Smith Faculty of Agriculture, Food and Environment, Department of Animal Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
² 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.
³ 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.
⁴ 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.

PMID: 24954479
DOI: 10.1016/j.ygcen.2014.05.028

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.

Keywords: 11-ketotestosterone; FSH; GnRH; Gonadotropin receptor; LH.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Antibodies / pharmacology*
Cichlids / growth & development
Cichlids / metabolism*
Enzyme-Linked Immunosorbent Assay
Feedback, Physiological / drug effects
Follicle Stimulating Hormone / chemistry
Follicle Stimulating Hormone / immunology*
Follicle Stimulating Hormone / metabolism
Gonadotropin-Releasing Hormone / pharmacology*
Luteinizing Hormone / chemistry
Luteinizing Hormone / immunology*
Luteinizing Hormone / metabolism
Models, Molecular
Protein Conformation
Reproduction / physiology
Testosterone / analogs & derivatives*
Testosterone / metabolism

Substances

Antibodies
Gonadotropin-Releasing Hormone
Testosterone
Luteinizing Hormone
Follicle Stimulating Hormone
11-ketotestosterone