High impact information on GNRHR

• GnRHs of the jawed vertebrates have a central achiral amino acid (glycine) that favors a type II' beta-turn such that the N- and C-terminal domains are closely apposed in binding the GnRH receptor [1].
• The chicken GnRH receptor had high affinity for mammalian GnRH (K(i) 4.1 +/- 1.2 nM), similar to the human receptor (K(i) 4.8 +/- 1.2 nM) [2].
• To explore the structural determinants of this, we have cloned a chicken pituitary GnRH receptor and demonstrated that it has marked differences in primary amino acid sequence (59% homology) and in its interactions with GnRH analogs [2].
• Complementary deoxyribonucleic acid cloning, gene expression, and ligand selectivity of a novel gonadotropin-releasing hormone receptor expressed in the pituitary and midbrain of Xenopus laevis [3].
• The order of potency of the GnRHs in stimulating inositol phosphate production in COS-1 cells transiently transfected with the X. laevis GnRH receptor cDNA was chicken GnRH II>salmon GnRH>mammalian GnRH [3].

Biological context of GNRHR

• In conclusion, we isolated a novel GNRHR and its splice variants in chickens, and spatial and temporal gene expression patterns suggest that this receptor plays an important role in the regulation of reproduction [4].
• Single-nucleotide polymorphisms and deletions were detected in the GHR, GNRHR and NPY genes [5].
• To determine whether the presence of the cytoplasmic tail was responsible for the more rapid internalization kinetics of the chicken GnRH-R we truncated the tail after the Ile336 residue (S337stop) [6].

Anatomical context of GNRHR

• Transcripts of this GnRH receptor are expressed in the pituitary and midbrain of X. laevis [3].
• These findings provide functional evidence in support of the novel hypothesis that goldfish ovarian follicles contain GnRH-receptor subtypes with different ligand selectivity mediating stimulatory and inhibitory actions of sGnRH and cGnRH in the goldfish ovary [7].
• Chicken GnRH II-like peptides and a GnRH receptor selective for chicken GnRH II in amphibian sympathetic ganglia [8].
• The presence of two endogenous forms of gonadotrophin-releasing hormone (GnRH) in the chicken hypothalamus (chicken GnRH-I ([Gln8]GnRH) and chicken GnRH-II ([His5, Trp7, Tyr8]GnRH)), and the stimulation of gonadotrophins by both forms, suggests the possible existence of GnRH receptor subtypes and gonadotroph subtypes in the chicken pituitary [9].
• Characterization of a pituitary GnRH-receptor from a perciform fish, Morone saxatilis: functional expression in a fish cell line [10].

Other interactions of GNRHR

• A dominance effect of NPY on age at first egg and an additive effect of GNRHR on the number of double-yolked eggs were found (P<0.05) [5].
• Real-time quantitative PCR was used to quantify pituitary expression of mRNAs encoding betaglycan, activin receptor (ActR) subtypes (type I, IIA), GnRH receptor (GnRH-R), LH beta subunit, FSH beta subunit and GAPDH [11].

Analytical, diagnostic and therapeutic context of GNRHR

• Using a combined strategy of PCR and rapid amplification of cDNA ends (RACE), a new GNRHR (chicken GNRHR2) and two splice variants were isolated in domestic fowl (Gallus gallus domesticus) [4].
• Northern blot analysis revealed a single GnRH-R transcript in the pituitary of approximately 2.3 kilobases [12].
• To evaluate the potential roles of sGnRH and cGnRH-II in both neural and reproductive tissues in goldfish, we studied the mRNA expression of sGnRH, cGnRH-II, and GnRH receptor (GnRH-R) in discrete brain areas, pituitary, ovary, and testis by a combined reverse transcription-polymerase chain reaction (RT-PCR) and Southern blot analysis [13].

References