ROLE OF ESTRADIOL ON PITUITARY GNRH TRANSCRIPTION PATHWAY FOR LH EXPRESSION IN LAGOSTOMUS MAXIMUS

PROIETTO S, CORSO MC, CORTASA S, SCHMIDT AR, INSERRA PIF, FEEHAN, K, DI GIORGIO NP, LUX-LANTOS V, VITULLO AD; HALPERIN J; DORFMAN, VERÓNICA B.

Congreso; Reunion Anual de Biociencias 2021; 2021

SAIC, SAI, NANOMED, AAFE

The massive release of pituitary luteinizing hormone (LH) triggersthe ovulatory event. This release is regulated by the combined actionof gonadotropin-releasing hormone (GnRH) and the steroidhormones, estradiol (E2) and progesterone (P4). At gonadotrophs,GnRH activates a transcriptional pathway that regulates the expression of EGR1 and SF1, both essential transcription factors requiredfor LHβ promoter activation. The plains vizcachas have shown reproductiveaxis activity during gestation with changes in hormonelevels around mid-pregnancy. The aim of this work was to determinethe role of E2 in the pituitary expression of Sf-1 and Egr-1 involvedin GnRH transcriptional activation pathway for LH expression. Differentin vivo and ex vivo approaches were developed (N=4/group):1- Non- pregnant females were ovariectomized (OVX) and treatedtwo days with low (OVX-2) or five days with high (OVX-5) dosesof E2 (5ug/kg or 15ug/kg, respectively). Sham and OVX animalswere used as control groups. 2- Pituitaries of non-pregnant femaleswere probed in a pulsatile assay under GnRH or GnRH+E2 supplementation.3- Pituitaries of non-pregnant females were probed ina pulsatile assay under different conditions: a) CTL, b) PPT (ERαagonist) + CYCLO (ERβ antagonist), c) MPP (ERα antagonist) +WAY (ERβ agonist), d) MPP+CYCLO. LH release was measuredby RIA, whereas pituitary GnRHR, Egr-1 and Sf-1 expression wasstudied by Western Blot. We observed that E2 induced significantchanges (p