Comparing sex hormones levels in Acipenser persicus at the onset of Autumnal migration

Abstract

Levels of two main steroid hormones in gonads, 17-B Estradiol (E2) and testosterone (T) were compared in males and females of Persian sturgeon at the start of autumnal migration to spawning rivers. Hormone levels were also studied for likely relationship with different stages of sexual maturity. The results showed that levels of T and E2 in females at the stage four of sexual maturity is significantly higher than the individuals with immature gonads (ovary in stages 2 and 3). We measured 11.81±2.860ng/ml and 7±1.15ng/ml of T and E2 in mature females compared to 0.2±0.09ng/ml and 0.736±0.161 ng/ml of T and E2 in immature females. Levels of the two hormones in males at different stages of sexual maturity showed that only testosterone was significantly different in mature and immature sturgeons (0.50±0.144 ng/ml and 14.3125±3.121ng/ml in mature and immature males. respectively) (P=0.04). In males and females with higher sexual maturity, differences between the two hormones were significant (T and E2 levels in females and males were 11.81±2.860ng/ml, 7±1.15ng/ml and 0.50±0.144ng/ml, 0.7023±0/212ng/ml, respectively). However, in immature fish of both sexes, only males showed significantly higher T levels (14.3125±3.121ng/ml in comparison with 0.2±0.09ng/ml). Disregarding the sexual maturity stages, we found significantly different levels of E2 in both sexes (4.779±1.827ng/ml in females and 0.709±0.121 ng/ml in males) (P=0.00). Statistical analyses indicated no correlation between fish age and levels of steroid hormones of the fish (at 90% confidence level).