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Hormone changes during the ovulatory cycle in goldfish.
1Department of Fisheries, Faculty of Agriculture, University of Tokyo, Japan.
General and Comparative Endocrinology
|February 1, 1988
Summary
Goldfish ovulation involves a distinct hormonal shift, with estradiol-17 beta (E2) peaking early and testosterone later, preceding a gonadotropin (GtH) surge. This hormonal pattern influences the timing of ovulation in female goldfish.
Area of Science:
- Reproductive endocrinology
- Fish biology
- Comparative physiology
Background:
- Understanding hormonal regulation is crucial for fish reproduction.
- Goldfish (Carassius auratus) are important models for aquaculture and research.
- Ovulatory cycles in fish are influenced by complex endocrine interactions.
Purpose of the Study:
- To characterize plasma hormone profiles during the ovulatory cycle in female goldfish.
- To compare hormone levels before and after ovulation.
- To elucidate the roles of gonadotropin (GtH), estradiol-17 beta (E2), and testosterone in goldfish ovulation.
Main Methods:
- Blood samples collected from female goldfish every 4 days over 3 months.
- Plasma hormone levels (GtH, E2, testosterone) measured.
- Hormone levels analyzed for the 3 days preceding and following ovulation.
Main Results:
- Gonadotropin (GtH) showed a surge associated with ovulation, with higher levels pre-surge.
- Plasma testosterone levels were significantly higher before ovulation than after.
- Estradiol-17 beta (E2) levels were low pre-ovulation, then elevated post-ovulation before declining.
Conclusions:
- Goldfish exhibit a sequential steroid hormone pattern: E2 early, then testosterone, preceding the GtH surge and ovulation.
- This E2-to-testosterone shift resembles salmonids but differs in timescale.
- Hormonal profiles and ovulation synchrony are influenced by physiological and environmental factors.