Activity of the porcine gonadotropin-releasing hormone receptor gene promoter is partially conferred by a distal gonadotrope specific element (GSE) within an upstream enhancing region, two proximal GSEs and a retinoid X receptor binding site.

BACKGROUND: Regulation of gonadotropin-releasing hormone (GnRH) receptor (GnRHR) numbers on gonadotropes within the anterior pituitary gland represents a critical point for control of reproductive function. Binding of GnRH to its receptor regulates follicle stimulating hormone (FSH) and luteinizing hormone (LH) release and levels of this G-protein coupled receptor on the surface of gonadotropes determines their sensitivity to GnRH pulses. While transcriptional regulation of this gene has been studied in mice, rats, humans and sheep, little is known about its regulation in the pig, an important agricultural species and human research model. METHODS: We isolated 5118 bp of 5' flanking sequence for the porcine GnRHR gene and generated luciferase reporter vectors. Deletion and mutation constructs were evaluated in gonadotrope-derived alphaT3-1 cells to determine regions important for gene transcription. Additionally, electrophoretic mobility shift assays (EMSAs) were performed to identify transcription factors binding to the GnRHR promoter. RESULTS: Transient transfections revealed that the GnRHR promoter was functional in alphaT3-1 cells but not in cells of non-gonadotrope origin. Mutation of the highly conserved gonadotrope specific element (GSE) located at -179/-171 of proximal promoter completely ablated luciferase activity, whereas mutation of another GSE at -315/-310 reduced activity by 34%. Consistent with this, EMSAs using alphaT3-1 nuclear extracts and a steroidogenic factor (SF)1 antibody confirmed SF1 binding to both GSEs. EMSAs also demonstrated that a retinoid X receptor (RXR) binding site at -279/-274 binds RXRalpha and RXRbeta and mutation of this site eliminated promoter activity. Transient transfection of alphaT3-1 cells with reporter vectors containing selective removal of 5' flanking region for the porcine GnRHR gene indicated that the -1915/-1431 segment was important for promoter activity. Definition of this region via transfection assays and EMSAs revealed an upstream enhancing region located at -1779/-1667 that increases porcine GnRHR gene expression in alphaT3-1 cells and includes a SF1 binding site at -1760/-1753. CONCLUSIONS: Porcine GnRHR promoter activity in alphaT3-1 cells is partially conferred by a distal GSE, two proximal GSEs and a RXR binding site. Basal gonadotrope expression of the porcine GnRHR gene uniquely involves three GSEs and RXR is newly identified as a regulator of GnRHR promoter activity.

Angled vas cutter for vasovasostomy: technique and results.

OBJECTIVE: To describe the technique and results of bilateral vasovasostomy using a 3-mm vas cutting forceps angled at 15° (catalog no. NHF-3.15; ASSI) for vasal transection. DESIGN: Retrospective chart review. Institutional review board approval was granted by Western Institutional Review Board. SETTING: Single vasectomy reversal center. PATIENT(S): Men who underwent a bilateral vasovasostomy at a single institution by a single surgeon between 2001 and 2012 and had a minimum of one semen analysis postoperatively or a reported natural conception. INTERVENTION(S): Before September 14, 2010, a straight-edge vas cutter was used on all vasovasostomy connections; 375 men received a bilateral vasovasostomy and met follow-up criteria. Beginning on September 14, 2010, an angled cutter was used on all vasovasostomy patients, with 194 men meeting the exclusion criteria. MAIN OUTCOME MEASURE(S): A minimum of 1 × 10(6) sperm reported on a postoperative semen analysis, or a reported natural conception was used to establish patency. RESULT(S): The overall vasovasostomy patency rate using the angled vas cutter was 99.5% and was 95.7% using the straight vas cutter. CONCLUSION(S): The development of an angled vas cutter provides an increased surface area for vasal wound healing to allow for larger tissue diameter for better healing, resulting in high patency rates after vasovasostomy.