Hossein Bazrafshan - Fisheries Department, Faculty of Natural Resources, University of Guilan, Sowmeh Sara, Iran
Bahram Falahatkar - Fisheries Department, Faculty of Natural Resources, University of Guilan, Sowmeh Sara, Iran

Injection of LHRH-A2 as the final maturation effective tool on ovulation, causechanges in the level of sex steroids which led to the final maturation of gametes. Inthis study, 18 sterlet females with an average weight of 1132.4 ± 248.5 g in threetreatments were considered and injected with 10 μg/kg LHRH-A2 intramuscularly intwo stages with 10 and 90 percent as priming and resolving doses, respectively. Bloodsamples were collected in three different stages; before injection (control), 12 hoursafter the first injection and after ovulation. Plasma levels of sex steroids (testosterone;T, progesterone; P, 17β estradiol; E2) were determined by radioimmunoassay. Datafrom the study showed, significant differences in T levels (P<0.05), so that themaximum (19.6 ± 0.8 ng/ml) and minimum levels (14.4 ± 2.7 ng/ml) of T wereobserved in 12 hours after the first injection and before injection, respectively.However, the levels of P and T were not significantly different (P> 0.05). Our resultrevealed that the injection of LHRH-A2 induced fluctuations in levels of hormonesinvolved in final oocyte maturation and sex steroids especially T in female culturedsterlet which has important role in ovulation.

LHRH-AR2R, Sterlet sturgeon, Sex steroid