PROLACTIN INDUCING FACTORS ARE UP-REGULATED IN THE HYPOTHALAMUS OF THE SOUTH AMERICAN PLAINS VIZCACHA FROM MID-PREGNANCY

SANTIAGO ANDRÉS CORTASA, SOFÍA PROIETTO, SCHMIDT ALEJANDRO RAÚL, PABLO FELIPE IGNACIO INSERRA, SANTIAGO ELÍAS CHARIF, MARÍA CLARA CORSO, ALFREDO DANIEL VITULLO; HALPERIN, JULIA; DORFMAN, VERÓNICA BERTA

Ciudad Autonoma de Buenos Aires

Congreso; Reunión Conjunta de Sociedades de BioCiencias; 2017

SAIC, SAIB, SAA, SAI, SAB, SAB, SAFE, SAFIS, SAH y SAP

Considering that prolactin (PRL) promotes luteal steroidogenesisin rodents and that the South American plains vizcacha(Lagostomus maximus) shows ovulation with corpora lutea (CL)formation at mid-gestation, with increased hypophyseal PRL andCL PRL receptor (PRLR) expression, we investigated the effect ofPRL over the expression of hypothalamic factors related with its ownproduction throughout the reproductive cycle of L. maximus. Firstly,adult non-pregnant (both non-ovulating and ovulating) and pregnant(early-, mid-, and term-gestation) vizcachas (n=5 per group) wereused to study hypothalamic PRLR and tyrosin hydroxylase (TH)immunoexpression and their colocalization by immunofluorescencewith confocal microscopy. In addition, we developed a hyperprolactinemiamodel by injecting non-pregnant females with two dosesof 10 mg/Kg sulpiride during 7 days (SULP, n=5) to study the influenceof PRL over the expression of its modulators. Animals injectedwith vehicle were used as controls (CTL, n=5). ANOVA followed byBonferroni or t-test were used to determine significant differencesamong groups (p<0.05). PRLR and TH expressions were studiedin arcuate nucleus (ARC). Significant increments in immunoreactivePRLR and TH areas, and in the number of neurons with expressionof both markers, were detected in mid- and term-pregnancy relatedto the other groups. Regarding to the hyperprolactinemia model,the efficiency of sulpiride was confirmed by a significant increase(p<0.05) in the hypophyseal PRL immunoreactivity in SULP vs CTL.In the hypothalamus, ARC Immunoreactive PRLR area and, PRLRand TH colocalization were significantly increased in SULP vs CTL.These results suggest a hypothalamic regulation of PRL expressionin the vizcacha from mid-pregnancy which supports its involvementin CL formation and maintenance of ovulation from mid- and up tothe end of pregnancy of L. maximus. Fundación Científica FelipeFiorellino, PIP110/14, PICT1281/2014