Molecular and functional analysis of GnRH2 in hypothalamic-pituitary-gonadal axis activation in Pampus argenteus

This study aimed to identify and characterize the gnrh2 gene in Pampus argenteus, and to systematically investigate the regulatory effects of synthetic GnRH2 decapeptide on the hypothalamic-pituitary-gonadal (HPG) axis through analyses of tissue distribution, expression patterns during gonadal development, and in vitro and in vivo functional experiments. In this study, the gnrh2 gene of the P. argenteus was successfully identified and characterized. Sequence analysis revealed that the gene possesses conserved structural features of the GnRH family, with a highly conserved decapeptide region (QHWSHGWYPG). Phylogenetic analysis indicated that P. argenteus GnRH2 clustered closely with teleost GnRH2 sequences. Tissue distribution analysis demonstrated that gnrh2 was most abundantly expressed in the pituitary, suggesting its critical role in the neuroendocrine regulation of reproduction. During gonadal development, gnrh2 expression exhibited dynamic, stage-dependent variations, with a significant increase at the maturation stage in both males and females. In vitro pituitary culture experiments showed that exogenous synthetic GnRH2 decapeptide altered the expression of lhβ and fshβ. In vivo intraperitoneal injection further revealed that synthetic GnRH2 decapeptide significantly upregulated the expression of gnrh2, lhr, lhβ, fshr, and fshβ in the hypothalamus and gonads, indicating that GnRH2 is associated with the transcriptional regulation of HPG axis-related genes and may be involved in reproductive processes. In summary, these findings suggest that GnRH2 may play a role in reproductive regulation in P. argenteus and provide a molecular basis for the artificial breeding and endocrine control of this species.