Zebrafish pituitary gene expression before and after sexual maturation

Abstract

Sexual maturation and somatic growth cessation are associated with adolescent development, which is precisely controlled by interconnected neuroendocrine regulatory pathways in the endogenous endocrine system. The pituitary gland is one of the key regulators of the endocrine system. By analyzing the RNA sequencing (RNA-seq) transcriptome before and after sexual maturation, in this study, we characterized the global gene expression patterns in zebrafish pituitaries at 45 and 90 days post-fertilization (dpf). A total of 15 043 annotated genes were expressed in the pituitary tissue, 3072 of which were differentially expressed with a greater than or equal to twofold change between pituitaries at 45 and 90 dpf. In the pituitary transcriptome, the most abundant transcript was gh. The expression levels of gh remained high even after sexual maturation at 90 dpf. Among the eight major pituitary hormone genes, lhb was the only gene that exhibited a significant change in its expression levels between 45 and 90 dpf. Significant changes in the pituitary transcripts included genes involved in the regulation of immune responses, bone metabolism, and hormone secretion processes during the juvenile-sexual maturity transition. Real-time quantitative PCR analysis was carried out to verify the RNA-seq transcriptome results and demonstrated that the expression patterns of the eight major pituitary hormone genes did not exhibit a significant gender difference at 90 dpf. For the first time, we report the quantitative global gene expression patterns at the juvenile and sexual maturity stages. These expression patterns may account for the dynamic neuroendocrine regulation observed in body metabolism.

Novel hypophysiotropic AgRP2 neurons and pineal cells revealed by BAC transgenesis in zebrafish

“…Pituitary α-MSH affects background adaption in teleost3, and zebrafish melanosomes disperse rapidly in response to α-MSH63. However, the lack of melanocortin receptor expression in the pituitary64 (and Supplementary Fig. S3) would suggest that such hypophysiotropic activity, if exists, is mediated by a different type of receptor.…”

Neuroendocrine regulation of somatic growth in fishes

“…In our laboratory, we observed a 25% increase in the body weight of PGC-null dnd morphants at 5 months of age compared with male sibling wildtype control zebrafish (unpublished data, Figure 1). This demonstrates the balance between the networks regulating somatic growth and reproduction Analysis of the global gene expression patterns in the zebrafish pituitary during the juvenile and sex maturation stages revealed that luteinizing hormone β (lhb) is the only pituitary hormone transcript to exhibit a significant change in expression between 45 and 90 dpf [48]. A decrease in spermatic parameters and reproductive success has been observed in GH overexpressing zebrafish males [124].…”

“…Similarly, their specific receptors, ghrh-rs, are abundant in the hypothalamus, telencephalon, spinal cord, diencephalon, and pituitary, but only present at low levels in the ovary [44,47]. Based on our recent pituitary transcriptome studies, the levels of both ghrh and ghrh-r expression were less than 1 RPKM in the zebrafish pituitary at both 45 and 90 d post-fertilization (dpf) [48]. Both ghrh and ghrh-r are expressed in the head region of zebrafish during the embryonic stage.…”

Depletion of suppressor of cytokine signaling-1a causes hepatic steatosis and insulin resistance in zebrafish

“…The constructions of the cDNA library and cDNA sequencing and comparison were performed by BGI. The expression analyses were performed as described previously (16).…”