Four gonadotropin releasing hormone receptor genes in Atlantic cod are differentially expressed in the brain and pituitary during puberty

Gen Comp Endocrinol. 2011 Sep 1;173(2):333-45. doi: 10.1016/j.ygcen.2011.06.002. Epub 2011 Jun 17.


Gonadotropin releasing hormones (GnRH) are an important part of the brain-pituitary-gonad axis in vertebrates. GnRH binding to its receptors (GnRH-R) stimulates synthesis and release of gonadotropins in the pituitary. GnRH-Rs also mediate other processes in the central nervous system such as reproductive behavior and neuromodulation. As many as five GnRH-R genes have been identified in two teleost fish species, but the function and phylogenetic relationship of these receptors is not fully understood. To gain a better understanding of the functional relationship between multiple GnRH-Rs in an important aquaculture species, the Atlantic cod (Gadus morhua), we identified four GnRH-Rs (gmGnRH-R) by RT-PCR, followed by full-length cloning and sequencing. The deduced amino acid sequences were used for phylogenetic analysis to identify conserved functional motifs and to clarify the relationship of gmGnRH-Rs with other vertebrate GnRH-Rs. The function of GnRH-R variants was investigated by quantitative PCR gene expression analysis in the brain and pituitary of female cod during a full reproductive cycle and in various peripheral tissues in sexually mature fish. Phylogenetic analysis revealed two types of teleost GnRH-Rs: Type I including gmGnRH-R1b and Type II including gmGnRH-R2a, gmGnRH-R2b and gmGnRH-R2c. All four gmGnRH-Rs are expressed in the brain, and gmGnRH-R1b, gmGnRH-R2a and gmGnRH-R2c are expressed in the pituitary. The only GnRH-R differentially expressed in the pituitary during the reproductive cycle is gmGnRH-R2a such that its expression is significantly increased during spawning. These data suggest that gmGnRH-R2a is the most likely candidate to mediate the hypophysiotropic function of GnRH in Atlantic cod.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Brain / metabolism*
  • Gadus morhua / metabolism*
  • Molecular Sequence Data
  • Phylogeny
  • Pituitary Gland / metabolism*
  • Polymerase Chain Reaction
  • Receptors, LHRH / chemistry*
  • Receptors, LHRH / classification
  • Receptors, LHRH / genetics
  • Receptors, LHRH / metabolism*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sequence Alignment


  • Receptors, LHRH