Hormone changes during the ovulatory cycle in goldfish

Involvement of steroid hormones in the preovulatory gonadotropin surge in female goldfish

“…Hormone changes during these reproductive cycles in goldfish have been well characterized (Schreck and Hopwood 1974;Stacey et al 1979;Kagawa et al 1983a;Kobayashi et al 1985Kobayashi et al , 1986Kobayashi et al , 1987bKobayashi et al , 1988. Ovulation in goldfish can be manipulated by changes in water temperature and photoperiod.…”

“…Furthermore, the spawning period can be prolonged by maintaining fish in warm (20°C) water on long photoperiod (14-16L). Female goldfish kept under these conditions will repeatedly ovulate over a period of several months (Kobayashi et al 1988). …”

Hormonal regulation of follicular atresia in teleost fish

“…Sexual maturity and gonadal development is associated with increased circulating levels of gonadotropins and the gonadal steroids (Kobayashi et al, 1987(Kobayashi et al, , 1988Habibi et al, 1989;Huggard et al, 1996Huggard et al, , 2002. In fish, the circulating concentrations of sex steroids such as testosterone and estradiol (E2) are important factors controlling the preovulatory GtH surge (for review, see Peter and Yu, 1997;Yaron et al, 2003).…”

Migratory Behaviors in Masu Salmon (Oncorhynchus masou) and the Influence of Endocrinological Factors

“…These results suggest that females ovulate during the last phase, or after their upstream swimming behavior ceased. Since spermiation and ovulation are controlled physiologically by pituitary hormones such as LH (Nagahama 1984;Kobayashi et al 1986Kobayashi et al , 1988, it was hypothesized that not only sex steroid hormones but also some other sex hormones may be involved in the occurrence of upstream swimming behavior. Investigations into masu salmon (Amano et al 1992(Amano et al , 1993, coho salmon (Swanson 1991), and rainbow trout (Prat et al 1996) indicate that LH levels increase with final ovarian maturation, especially during ovulation.…”