Project description:Identifying the early gene program induced by GnRH would help understand how GnRH-activated signaling pathways modulate gonadotrope secretory response. We previously analyzed GnRH-induced early genes in LbT2 cells, however these lack GnRH self-potentiation, a physiological attribute of gonadotropes. To minimize cellular heterogeneity, rat primary pituitary cultures were enriched for gonadotropes by 40-60% using a sedimentation gradient. Given the limited number of gonadotropes, RNA was amplified prior to microarray analysis. Thirty-three genes were up-regulated 40 minutes after GnRH stimulation. Real-time PCR confirmed regulation of several transcripts including fosB, c-fos, egr-2 and rap1b, a small GTPase and member of the Ras family. GnRH stimulated rap1b gene expression in gonadotropes, measured by a sensitive single cell assay. Immunocytochemistry revealed increased Rap1 protein in GnRH-stimulated gonadotropes. These data establish rap1b as a novel gene rapidly induced by GnRH and a candidate to modulate gonadotropin secretion in rat gonadotropes. Primary rat gonadotrope cells were exposed to 10 nM GnRH for 40 min, then harvested and processed for RNA extraction using a Qiagen RNeasy mini kit (Qiagen, Valencia, CA). A total of 12 Affymetrix Rat Expression Array 230 v2.0, namely 6 GnRH-treated and 6 vehicle-treated samples, each containing 31,000 gene clusters, were used. Data analysis was performed by Affymetrix GeneChip Operating System (GCOS). A gene was considered to be up-regulated by GnRH if there is at least 50% concordance across multiple pairwise comparisons of GnRH- vs. vehicle-treated microarrays, and if the fold-change was at least 1.50.
Project description:Identifying the early gene program induced by GnRH would help understand how GnRH-activated signaling pathways modulate gonadotrope secretory response. We previously analyzed GnRH-induced early genes in LbT2 cells, however these lack GnRH self-potentiation, a physiological attribute of gonadotropes. To minimize cellular heterogeneity, rat primary pituitary cultures were enriched for gonadotropes by 40-60% using a sedimentation gradient. Given the limited number of gonadotropes, RNA was amplified prior to microarray analysis. Thirty-three genes were up-regulated 40 minutes after GnRH stimulation. Real-time PCR confirmed regulation of several transcripts including fosB, c-fos, egr-2 and rap1b, a small GTPase and member of the Ras family. GnRH stimulated rap1b gene expression in gonadotropes, measured by a sensitive single cell assay. Immunocytochemistry revealed increased Rap1 protein in GnRH-stimulated gonadotropes. These data establish rap1b as a novel gene rapidly induced by GnRH and a candidate to modulate gonadotropin secretion in rat gonadotropes.
Project description:Analysis of hormone effects on irradiated LBNF1 rat testes, which contain only somatic cells except for a few type A spermatgogonia. Rats were treated for 2 weeks with either sham treatment (group X), hormonal ablation (GnRH antagonist and the androgen receptor antagonist flutamide, group XAF), testosterone supplementation (GnRH antagonist and testosterone, group XAT), and FSH supplementation ((GnRH antagonist, androgen receptor antagonist, and FSH, group XAFF). Results provide insight into identifying genes in the somatic testis cells regulated by testosterone, LH, or FSH.
Project description:Gonadotropin-releasing hormone (GnRH) governs reproduction in vertebrates by regulating pituitary gonadotropins. Zebrafish, however, is an exception as gnrh3–/– fish, which lack the hypophysiotropic GnRH3, are fertile, suggesting that zebrafish utilizes a Gnrh-independent mechanism to regulate reproduction. To elucidate the role of Gnrh3 and the Gnrh-independent mechanisms that regulate the pituitary gonadotropes, we profiled the gene expression in individual pituitary cells of wild-type and gnrh–/– adult female zebrafish and identified transcriptionally defined cell types. The classical Lh and Fsh gonadotropes expressed both gonadotropin beta subunits with a ratio of 13:1 (lhb:fshb) and 40:1 (fshb:lhb), respectively. We discovered that Lh gonadotropes predominantly express genes encoding receptors for Gnrh (gnrhr2), thyroid hormone, estrogen, dopamine, and steroidogenic factor 1 (SF1). No Gnrh receptor expression was enriched in Fsh gonadotropes, instead, the expression of cholecystokinin receptor (cckrb) and galanin receptor (gal1rb) were enriched in these cells. The hereditary loss of Gnrh3 gene resulted in downregulation of fshb in Lh gonadotropes. Likewise, targeted chemogenetic ablation of Gnrh3 neurons led to a decrease in the number of fshb+/lhb+ cells. Our studies suggest that Gnrh3 directly acts on Lh gonadotropes through Gnrhr2, but the outcome of this interaction is still unknown. Gnrh3 also regulates fshb expression, probably via a non-Gnrh receptor route. Altogether, while Lh secretion and synthesis are likely regulated by multiple factors in a Gnrh-independent manner, Gnrh3 seems to play a role in the cellular organization of the pituitary in zebrafish.
Project description:In order to establish a rat embryonic stem cell transcriptome, mRNA from rESC cell line DAc8, the first male germline competent rat ESC line to be described and the first to be used to generate a knockout rat model was characterized using RNA sequencing (RNA-seq) analysis.