Thermal Stress Affects Gonadal Maturation by Regulating GnRH, GnRH Receptor, APGWamide, and Serotonin Receptor Gene Expression in Male Pacific Abalone, Haliotis discus hannai During Breeding Season

Temperature has crucial effects on gonadal development and reproduction of abalone. To understand the impact thermal stress molecular physiological processes triggering regulation reproduction, changes in mRNA expression neuroendocrine genes encoding two abalone gonadotropin-releasing hormone ( Hdh-GnRH , Hdh-GnRH-like peptide ), GnRH receptor Hdh-GnRH-R Hdh-APGWamide serotonin 5-HT hdh a heat shock protein HSP70 were examined ganglia testis male Pacific Haliotis discus hannai ). Abalone exposed to low water temperature (LWT) high (HWT) early peak breeding seasons for 7 days. Then, gonadosomatic index (GSI) was calculated, relative gene measured by qRT-PCR, levels testosterone hemolymph also ELISA during season. GSI did not show any significant However, it significantly decreased LWT- or HWT-exposed compared normal (NWT) group In season, all five between LWT HWT groups day-7. NWT group, expressions different tissues both abalone, such as cerebral ganglion (CG) testis; pleuropedal (PPG) branchial (BG); CG, PPG, PPG testis. Interestingly, increased but group. Expression after exposure HWT. Hemolymph those Altogether, these results denote that repressive effect maturation regulating testosterone.