Identification of important proteins from the gonads and pituitary involved in the gonad development of Amur sturgeon, Acipenser schrenckii, regulated by GnRH-a treatment by iTRAQ-based analysis

Abstract

•Gonadotropin-releasing hormone (GnRH) has been proven to promote ovarian development. Exogenous GnRH-a blocks the normal functions of the GnRH receptor, leading to a decrease in ovarian development. In this study, we aimed to select important metabolic pathways and proteins involved in the gonad development of the juvenile Acipenser schrenckii through the measurement of steroid hormones and proteome profiling analysis after GnRH-a treatment. The results showed that 3 μg/kg GnRH-a treatment was proven to have the most significant flare up effect in the juvenile A. schrenckii after 7 d of treatment, based on the measurements of steroid hormones. Five gonads and pituitaries were pooled to form one biological replicate at 7 days after 3 μg/kg GnRH-a treatment and GFP treatment, respectively, and three biological replicates were performed for both groups. Proteome profiling analysis revealed that the number of differentially expressed proteins (DEPs) in the gonad was greater than that in the pituitary, indicating that GnRH-a has more regulatory effects on the gonad than on the pituitary. Moreover, Kyoto encyclopedia of genes and genomes analysis of DEPs indicated that signal transduction and endocrine system metabolic pathways and their co-DEPs played essential roles in the gonad development of A. schrenckii. According to the MRM analysis, protein kinase C was the most upregulated protein in both the gonad and pituitary after GnRH-a treatment, whereas estradiol 17β- dehydrogenase was the most downregulated protein. This study provides the basis for further analysis of the effects of GnRH on gonad development in A. schrenckii.