Neuroestradiol is involved in GnRH modulation during pregnancy in the South American plains vizcacha, Lagostomus maximus.

SANTIAGO ELIAS CHARIF, PABLO IGNACIO FELIPE INSERRA, NOELIA PAULA DI GIORGIO, ALEJANDRO RAUL SCHMIDT; HALPERIN J; VICTORIA LUX-LANTOS, CANDELA ROCIO GONZALEZ, ALFREDO DANIEL VITULLO, VERONICA BERTA DORFMAN

Mar del Plata

Congreso; LXI Reunión Científica Anual. Sociedad Argentina de Investigación Clínica (SAIC); 2016

Neuroendocrine areas involved in the reproductive controlhave sho􀁙n aromatase 􀀊A􀀴􀀱􀀋 expression and activity suggestinglocal synthesis of estradiol 􀀊E􀀔􀀋. 􀀩onadotropin􀀏releasing hormone􀀊􀀩n􀀴H􀀋 surge is affected by E􀀔 availability. The South Americanplains vizcacha, Lagostomus maximus, sho􀁙s ovulation up to 􀀚􀀒􀀒oocytes per reproductive cycle and ovulation at mid􀀏gestation. Theaim of this 􀁙or􀁍 􀁙as to analyze hypothalamic expression of A􀀴􀀱 inthe vizcacha at different gestational time􀀏points, and its relationship􀁙ith 􀀩n􀀴H expression and delivery. Hypothalami of non􀀏pregnantnon􀀏ovulating 􀀊􀀰􀀲􀀰􀀱􀀋, early􀀏pregnant 􀀊E􀀲􀀋, mid􀀏pregnant 􀀊􀀯􀀲􀀋,and term􀀏pregnant 􀀊T􀀲􀀋 female vizcachas 􀀊n􀀟􀀘 per group􀀋 􀁙ereused to study A􀀴􀀱 and 􀀩n􀀴H m􀀴􀀰A by q􀀲C􀀴 and protein expressionby 􀀹estern􀀏blot or 􀀴􀀫A respectively􀀝 hypothalamic colocalizationof A􀀴􀀱 and 􀀩n􀀴H 􀁙as evaluated by immunofluorescence andconfocal microscopy, and 􀀩n􀀴H pulsatility under A􀀴􀀱 action usingletrozole 􀀊A􀀴􀀱 specific inhibitor􀀋 by 􀀴􀀫A. A significant incrementin A􀀴􀀱 expression 􀀊p􀀞􀀒.􀀒􀀗􀀋 􀁙as detected in 􀀯􀀲 vs other groups,and these results 􀁙ere correlated 􀁙ith 􀀩n􀀴H expression. Cytoplasmiclocalization of A􀀴􀀱 and 􀀩n􀀴H 􀁙as observed in neuronsof preoptic area 􀀊􀀲􀀱A􀀋 and supraoptic nucleus 􀀊S􀀱􀀰􀀋. All 􀀩n􀀴Hneurons sho􀁙ed A􀀴􀀱 expression and the quantification of neuronsco􀀏expressing both proteins did not sho􀁙 statistical differencesamong groups. To investigate neuroE􀀔 action on 􀀩n􀀴H pulsatility,hypothalamic explants 􀁙ere treated 􀁙ith letrozole and 􀀩n􀀴Hsecretion 􀁙as evaluated. Total 􀀩n􀀴H secretion 􀁙as significantlydecreased by letrozole vs. control􀀝 ho􀁙ever, pulsatile frequencydid not change. The correlation bet􀁙een 􀀩n􀀴H and aromataseexpression at mid􀀏gestation, and their co􀀏localization in the hypothalamicneurons suggests the modulation 􀀩n􀀴H expressionby neuroE􀀔 as part of a reproductive strategy of the vizcacha toassure 􀀩n􀀴H synthesis during pregnancy