RT - Journal Article T1 - Effects of letrozole, non-steroidal aromatase inhibitor, on serum sex steroid levels, oocyte diameter and gonadosomatic index (GSI) in rainbow trout (Oncorhynchus mykiss) JF - IFRO YR - 2015 JO - IFRO VO - 14 IS - 1 UR - http://jifro.ir/article-1-1865-en.html SP - 289 EP - 301 K1 - Aromatase inhibitor K1 - Sex steroid K1 - GSI K1 - Oncorhynchus mykiss AB - The objective of this study was to contribute to investigate the efficacy of letrozole, a potent non-steroidal aromatase inhibitor, on serum sex steroid levels and oocyte growth in rainbow trout females. Serum steroid levels were measured using an indirect enzyme-linked immunosorbent assay (ELISA) before and 22 days after an initial injection with 1, 2.5 mg kg-1 and subsequent weekly injection with 2.5 mg kg-1letrozole. After the last blood collection, gonad tissues were removed and oocyte diameter and GSI were determined. In all groups treated with letrozole, serum 17β- esteradiol levels (E2) decreased significantly and inversely serum 17α-20ß dihydroxy-4 pregnen- 3- one (17α-20ß-P), testosterone(T) levels increased significantly from 6 to 96 h after injection (p LA eng UL http://jifro.ir/article-1-1865-en.html M3 ER -