GnRH EXPRESSION AT HYPOTHALAMUS OF LAGOSTOMUS MAXIMUS (PLAINS VIZCACHA)

DORFMAN VERONICA B.; FRAUNHOFFER NICOLAS A.; INSERRA PABLO IF.; LOIDL CESAR F.; VITULLO ALFREDO D.

Buenos aires

Jornada; XI Jornadas anuales de la Sociedad Argentina de Biología; 2009

Sociedad Argentina de Biología

Gonadotropin-releasing hormone (GnRH) is synthesized in a pulsatil manner from puberty to menopause, except during pregnancy, to regulate folliculogenesis. Plains Vizcachas show natural polyovulation with corpus luteum abundance and ovulation during pregnancy. To understand the modulation of hypothalamus-pituitary - gonadal axis (HPG), the aim of this work was to characterize hypothalamic GnRH expression in the vizcacha. Vizcachas of both sexes (n=5 each), captured at Estación de Cría de Animales Silvestres (ECAS), were anesthetized with ketamin-xilacin and sacrificed with Eutanyl®. Coronal brain slices were dyed with Hematoxylin and the hypothalamic regions Preoptic Area (POA,Ventromedial Nucleus (VMN, Medial Eminence (ME) and Arcuato Nucleus (AN) were localized by comparison with histological brain atlas of rat and guinea pig. Specific immunolocalization of GnRH was observed in the cytoplasm of neurons at POA and AN (at both,somas y ramifications), and at varicosities of POA, VMN and ME. Similar GnRH distribution was detected in animals of both sexes. GnRH expression level was studied in male and female plains vizcachas and no significant differences were determined between sexes. Tissue GnRH localization and its description at hypothalamic regions involved on HPG axis in this animal would allow the comprehension of HPG axis modulation with extrapolation into human fertility pathologies.