Exploring the Sex-Differentiated Transcription of GnRH1/GnRHR1 Signaling in Hamster

Gonadotropin-releasing hormone 1 (GnRH1) and its receptor (GnRHR1) are central neuropeptides on the hypothalamic-hypophysis-gonadal (HHG) axis and play key roles in vertebrate reproduction. Although GnRH1/GnRHR1 signaling has been extensively studied in models such as mouse, rat, zebrafish, and human, knowledge from other species is limited. This work used cloning, Sanger sequencing, and qPCR to highlight the molecular structure, evolutionary history, and sex-differentiated transcription of GnRH1/GnRHR1 signaling from hamster. These findings showed that GnRH1/GnRHR1 hamster proteins exhibit a molecular evolutionary history highly similar for peptides reported in other species and with which they share a high degree of structural homology. Expression profiles indicated a GnRH1 transcript in several tissues with higher expression levels in testes, adrenals, uterus, epididymis, female hypothalamus, and Harderian glands. GnRHR1 expression levels were seen exclusively in male and female hypophysis with higher levels in female hypophysis. Expression levels showed significant differences for GnRH1 in several tissues during estrous; GnRHR1 expression during estrous was detected only in hypophysis with increased expression levels seen during metestrus and diestrus. These results suggest a highly conserved homology of GnRHR1/GnRHR1 signaling, thus highlighting its evolutionary importance. These expression levels underscore the importance of GnRHR1 as a master regulator of reproductive endocrinology and could implicate hamster peptides as potential therapeutic biological models for human endocrine diseases.