EFFECTS OF ESTRADIOL ON GNRH RECEPTOR SIGNALING PATHWAY AND LH RELEASE IN THE SOUTH AMERICAN PLAINS VIZCACHA (LAGOSTOMUS MAXIMUS).

PROIETTO, SOFIA; CORTASA, SANTIAGO ANDRES; SCHMIDT, ALEJANDRO RAÚL; CORSO, MARIA CLARA; INSERRA, PABLO IGNACIO FELIPE; DI GIORGIO NP, LUX-LANTOS V; HALPERIN, JULIA; ALFREDO DANIEL VITULLO; DORFMAN BERTA VERONICA

Mar del Plata

Congreso; LXIII Reunion Anual de la Sociedad Argentina de Investigacion Clinica; 2018

Sociedad Argentina de Investigacion Clinica

<!-- /* Font Definitions */@font-face{font-family:Calibri;panose-1:2 15 5 2 2 2 4 3 2 4;mso-font-charset:0;mso-generic-font-family:auto;mso-font-pitch:variable;mso-font-signature:-520092929 1073786111 9 0 415 0;} /* Style Definitions */p.MsoNormal, li.MsoNormal, div.MsoNormal{mso-style-unhide:no;mso-style-qformat:yes;mso-style-parent:"";margin-top:0cm;margin-right:0cm;margin-bottom:10.0pt;margin-left:0cm;line-height:115%;mso-pagination:widow-orphan;font-size:11.0pt;font-family:Calibri;mso-ascii-font-family:Calibri;mso-ascii-theme-font:minor-latin;mso-fareast-font-family:Calibri;mso-fareast-theme-font:minor-latin;mso-hansi-font-family:Calibri;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:minor-bidi;mso-ansi-language:ES-AR;}.MsoChpDefault{mso-style-type:export-only;mso-default-props:yes;font-size:11.0pt;mso-ansi-font-size:11.0pt;mso-bidi-font-size:11.0pt;font-family:Calibri;mso-ascii-font-family:Calibri;mso-ascii-theme-font:minor-latin;mso-fareast-font-family:Calibri;mso-fareast-theme-font:minor-latin;mso-hansi-font-family:Calibri;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:minor-bidi;mso-ansi-language:EN-US;}.MsoPapDefault{mso-style-type:export-only;margin-bottom:8.0pt;line-height:107%;}@page WordSection1{size:612.0pt 792.0pt;margin:72.0pt 90.0pt 72.0pt 90.0pt;mso-header-margin:36.0pt;mso-footer-margin:36.0pt;mso-paper-source:0;}div.WordSection1{page:WordSection1;}-->Pituitary expressionof gonadotropin-releasing hormone (GnRH) receptor (GnRHR) is regulated byestradiol mainly through its receptor ERalpha. The activation of GnRHR pathwayinvolves the induction of transcription factors such as Egr-1 and Sf-1, resultingin luteinizing hormone (LH) expression. Vizcachas show reproductive axis activityduring gestation with increased LH delivery at mid-pregnancy. The aim of thiswork was to determine the effect of estradiol on the GnRH signaling pathway andits final target LH. Adult vizcachas were used under two experimentalconditions: 1) Non-pregnant females (NPf); 2) Ovariectomized NPf (OVX) treatedwith low (OVX-5) or high (OVX-15) doses of estradiol (5ug/kg or 15ug/kg,respectively). SHAM females were used as control (n=4/group). The success of estradioltreatments was corroborated by serum estradiol measure by ELISA. Pituitary LHpulsatility was assayed with or without GnRH supplementation and LH released measuredby RIA, whereas pituitary GnRHR, ERalpha, Egr-1 and Sf-1 were studied byimmunohistochemistry and PCR. A significant induction of LH release wasdetermined in pituitaries of NPf supplemented with GnRH (p<0.001). Inaddition, the pituitaries incubated with GnRH showed a significant increase in GnRHRand Egr-1 (p<0.05) protein confirming the activation of GnRHR intracellularsignaling. The second approach depicted a significant increase of LH release inOVX and OVX-15 animals compared to SHAM and OVX-5 (p<0.01). These changeswere matched by decreases of GnRHR and Egr-1 in OVX but an increase in OVX-15 (p<0.05).Finally, a concordant coexpression was determined between ERalpha and GnRHR inOVX. These results suggest that estradiol affects GnRHR signaling pathway andLH delivery in a dose-dependent manner. (PIP110/14,PICT1281/2014, Fundación Científica