DIFFERENCIAL 3-ALPHA-HOR GENIC EXPRESSION IN PUBERTY

GIULIANI F; ESCUDERO C; GARCÍA S; YUNES R; CABRERA R

Ciudad de la Punta, San Luis.

Congreso; XXVII REUNION CIENTIFICA ANUAL DE LA SOCIEDAD DE BIOLOGIA DE CUYO; 2009

Sociedad de Biologia de Cuyo.

The onset of puberty in female rats is triggered by an early pulsatile GnRH release from hypothalamus. This event becomes evident when vaginal opening (VO) occurs. GnRH release is controlled by glutamatergic inputs that are regulated, among others factors, by neurosteroids such as allopregnanolone (Allo). In a previous work of our group we have demonstrated that Allo increases glutamate release in medial basal hypothalamus (MBH) and preoptic area (POA) of pubertal (P) and VO rats. One important point to be addressed is how neurosteroidogenic enzymes are expressed in MBH and POA at different stages of the reproductive life. The enzyme 3á-hydroxysteroid oxidoreductase (3áHOR) catalyzes the synthesis of Allo. The aim of this work was to determine if there is a differential gene expression of 3áHOR in MBH and POA of prepubertal (PP), P and VO rats. RNA was isolated from pooled MBH and POA obtained from PP (30d), P (50d) and VO (39d on average) rats (n=3 per group). Multiplex RT-PCR amplification was performed by using specific primers for 3áHOR and cyclophilin (housekeeping gene). Relative optic density of the bands was obtained after electrophoresis and ethidium bromide dying. The results were analyzed by ANOVA 1 and Tukey’s post hoc test (p<0.05 was considered significant). The expression of 3áHOR was increased in VO rats compared with PP (p<0.01) and P (p<0.05) rats. These results suggest that Allo levels would be increased in VO rats and that this neurosteroid might play an important role as a regulator of the onset of puberty.