Abstract
In this investigation, serum steroid hormones such as testosterone (T), 17β-estradiol (E2) and progesterone (P) in 12 female of the migratory population of Common carp (Cyprinus carpio) in southeast of Caspian Sea during a year from May 2011 to May 2012 were studied. The results of present study revealed that changes in levels of steroid hormones, (E2) and (T) were closely correlated to ovarian development. There was significant difference in level of 17 β- estradiol between autumn and winter seasons that the highest of 17-β estradiol level was observed in autumn season. In the case of progesterone hormone, higher levels was recorded in summer season and there was significant difference between summer and spring seasons and lower level of testosterone was observed in spring season.
Highlights
Sex steroid hormones play important roles in many physiological processes, in the reproduction of vertebrates
The aim of this work was to investigate the seasonal cycle of the gonadal steroids testosterone (T), 11ketotestosterone (11-KT), and 17b-estradiol (E2) in the serum of wild-caught populations of Cyprinus carpio from the southern Caspian Sea
Steroid hormones analysis during four seasons showed that there was no significant differences in level of 17βstradiol among spring, autumn and between autumn and winter seasons and higher level belong to autumn season
Summary
Sex steroid hormones play important roles in many physiological processes, in the reproduction of vertebrates. In many species of teleost, three sex steroid hormones, 17β-estradiol (E2), 11-ketotestosterone (11-KT) and 17 α20 β- dihydroxy-4-pregnen-3-one (DHP) are abundantly produced in gonadal tissues under the control of pituitary gonadotropins (GTH), and are essential for critical steps of gametogenesis (Wallace & Browder 1985; Agahama & Yamashita 2008; Miura et al 1991). The association of changes in gonadal development with plasma levels of gonadal steroids has proven to be a valuable tool for understanding the endocrine control of reproduction in teleosts. In teleosts, vitellogenesis and final oocyte maturation are regulated by gonadotropins via steroids secreted by the Granolosa and Theca cells of developing and mature oocytes.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
