Germinal vesicle breakdown rates in oocytes and steroid levels in blood and ovarian fluid of the Persian sturgeon Acipenser persicus

In the present study, the steroids [Cortisol (C), testosterone (T), 11-ketotestosterone (11-KT), progesterone (P), 17,20ß,21-trihydroxy-4-pregnen-3-one (20βS), 17α,20β dihydroxy-4-pregnen-3-one (DHP) and 17α, hydroxyprogesterone (OHP)] in both blood serum (BS) and ovarian fluid (OF) as well as the rate of Germinal Vesicle Breakdown (GVBD) were measured for the Persian sturgeon, Acipenser persicus. The high positive correlations were found between 20ßS and P levels in both OF and BS. Additionally, 20ßS and P exhibited the positive correlation with percentage of GVBD while a significant negative correlation was found between Polarization Index (PI) values and percentage of GVBD. The levels of 20ßS and P in both BS and OF were significantly higher in females with high GVBD rate than in females with the lowest GVBD rate. Therefore, the percentage of GVBD may be affected by 20ßS and P levels in both OF and BS as well as by developmental stage of oocytes.