Maintenance of Atlantic salmon (Salmo salar) at elevated temperature inhibits cytochrome P450 aromatase activity in isolated ovarian follicles

• Main Authors: Marianne Watts, Ned W. Pankhurst, Henry R. King
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2004
• Subjects: Key words; Atlantic salmon; temperature; reproduction; vitellogenesis; 17β-estradiol; aromatase; steroidogenesis 2; Salmo salar
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.503.6471; http://www98.griffith.edu.au/dspace/bitstream/handle/10072/14625/marianne_temp1_revised.pdf;jsessionid=5DEADE3C163E95F07FFA232749342F43?sequence=1

Atlantic salmon (Salmo salar) broodstock were transferred from natural (12– 16 oC) to controlled temperatures of 14, 18 or 22 oC for 3 months during vitellogenesis. Fertility and survival were significantly reduced in eggs from broodstock held at 22oC relative to 14 or 18 oC. Endocrine mechanisms were disrupted after only one month at 22oC, as evidenced by decreased plasma vitellogenin (Vtg) and increased plasma testosterone (T) levels and, at later stages, decreased levels of plasma 17β-estradiol (E2). In vitro incubations of isolated ovarian follicles were carried out at monthly intervals, with follicles exposed to human chorionic gonadotropin, N, 2-0-dibutyryladenosine 3,5-cyclic monophosphate, and the gonadal steroid precursors 17-hydroxyprogesterone, androstenedione and T. After one month of exposure to controlled temperature, T synthesis was generally enhanced in response to all treatments at all temperatures, but E2 synthesis was inhibited at 22oC, suggesting temperature impairment of cytochrome P450 aromatase (P450arom) synthesis or activity. The effect became less marked as follicles matured suggesting that temperature sensitivity is stage dependent. The results of this study suggest that the inhibitory effects of elevated temperature on E2 and Vtg synthesis, and subsequent egg development found in the present and earlier studies, arise at least partly, from temperature modulation of P450arom.