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ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Livestock Bio-Systems » Research » Publications at this Location » Publication #350819
Research Project: Improving Lifetime Productivity in Swine

Location: Livestock Bio-Systems

Title: GnRH-II and its receptor are critical regulators of testicular steroidogenesis in swine

Author
item DESAULNIERS, AMY - University Of Nebraska
item CEDERBERG, REBECCA - University Of Nebraska
item Lents, Clay
item WHITE, BRETT - University Of Nebraska

Submitted to: Society for the Study of Reproduction Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2018
Publication Date: 7/10/2018
Citation: Desaulniers, A.T., Cederberg, R.A., Lents, C.A., White, B.R. 2018. GnRH-II and its receptor are critical regulators of testicular steroidogenesis in swine [abstract]. Society for the Study of Reproduction 51st Annual Meeting, 10-13 July 2018, New Orleans, LA. p. 111-112. Available: https://www.ssr.org/sites/ssr.org/files/2018_annual_meeting_abstracts_updated.pdf

Interpretive Summary:

Technical Abstract: The second mammalian form of GnRH (GnRH-II) and its receptor (GnRHR-II) are produced in one livestock species, the pig. However, the interaction of GnRH-II with its receptor does not stimulate gonadotropin secretion. Instead, both are abundantly produced in the gonads and have been implicated in autocrine/paracrine regulation of steroidogenesis. Our data suggests that GnRH-II from seminiferous tubules interacts with GnRHR-II on porcine Leydig cells to stimulate LH-independent testosterone biosynthesis. To further study the role of GnRH-II and its receptor, our laboratory generated a knockdown (KD) swine line with 70% lower testicular GnRHR-II expression and 80% diminished basal testosterone concentrations. The objective of this study was to assess Leydig cell functionality in GnRHR-II KD (n = 4) and littermate control (n = 2) males. In the first experiment, blood was serially collected via indwelling catheters prior to and after intravenous treatment with human chorionic gonadotropin (hCG; 30 IU/kg BW); serum testosterone concentrations were measured via radioimmunoassay (RIA). A line (GnRHR-II KD versus control) x time interaction was detected (P 0.10). In both lines, testosterone levels were reduced below basal concentrations 2 h post-treatment, staying suppressed for the remainder of sampling (P 0.10), suggesting adrenal origin. Concentrations of all 10 steroid hormones did not differ between genotypes after castration (P > 0.10). These data demonstrate that knockdown of testicular GnRHR-II ablates gonadal steroidogenesis, indicating that GnRH-II and its receptor are critical regulators of steroid hormone production within porcine Leydig cells. Supported by USDA/NIFA AFRI-ELI predoctoral fellowship (2017-67011-26036; ATD) and AFRI (2017-67015-26508; BRW) funds.