Seasonal variation of steroid synthesis of Rhinella arenarum follicles

ARIAS TORRES AJ, BULACIOS G, TRACANNA MI, ZELARAYÁN LI

Tucum¨¢n

Jornada; XXX Jornadas Científicas Asociación de Biología de Tucumán; 2013

SEASONAL VARIATION OF STEROID SYNTHESIS OF Rhinella arenarum FOLLICLES Arias Torres AJ 1, Bulacios G 2, Tracanna MI 2, Zelarayán LI 2. INSIBIO-CONICET1 y FBQF-UNT2. Chacabuco 461. CP. 4000. Tucumán. anajoarias@hotmail.com Although steroids have been considered the mediators of the in vivo maturation of the oocyte of X. laevis, has not yet been clarified which is physiological regulator of such process since both androgens and progestins, are powerful promoters of the maturation of the oocyte of that species. We decided to study the participation of the ovarian follicle in the seasonal synthesis of steroids in adult female ovaries by TLC and its relationship with the oocyte maturation. Complete follicles (fc) from ovaries of R. arenarum were obtained in different seasons. The fc were incubated in saline amphibian solution (RA) in the presence or absence of hCG (10UI/mL) for 3, 6, 9 and 20 h. Steroids were extracted from the incubation medium and analyzed by TLC. The fc remained in RA and rupture of the germinal vesicle (RVG) was controlled after 24 h. The results indicate that the winter fc incubated with hCG release P4 after 3 h of incubation. Only matured the fc incubated for 20 h with hCG (60% RVG). In the summer, the stimulated follicles released T at all times analyzed. 35% of them matured at 6 h, 48% at 9 h and 100% of the fc ovulated in vitro at 20 h of incubation. The fc control both summer and winter not matured (0% RVG) and steroids in the incubation media were not detected. During the winter, P4 production increases in the fc incubated in the presence of hCG, while in the same period T levels were not detected by TLC. In the summer, T was the predominant steroid produced in the fc under stimulation gonadotrofico. These results provide evidence of seasonal changes in ovarian steroidogenesis of R. Arenarum and the relationship wiht oocyte maturation.