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Gonadectomy and Blood Sampling Procedures in the Small Size Teleost Model Japanese Medaka (Oryzias latipes)
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Stressors, glucocorticoids and ovarian function in teleosts
J F Leatherland1, M Li, S Barkataki
1Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ontario, N1G 2W1, Canada. jleather@ovc.uoguelph.ca
Journal of Fish Biology
|August 27, 2010
Summary
Glucocorticoids impact teleost ovarian function through complex direct and indirect stress responses. Recent research clarifies their role in the hypothalamus-pituitary-ovarian axis and energy regulation.
Area of Science:
- Endocrinology
- Fish Biology
- Reproductive Physiology
Background:
- Teleost ovarian function is influenced by the stress response.
- The hypothalamus-pituitary-ovarian (HPO) axis integrates environmental and physiological signals.
- Glucocorticoids play a role in energy metabolism and stress adaptation.
Purpose of the Study:
- To re-examine the direct and indirect actions of glucocorticoids on teleost ovarian function.
- To integrate recent advances in stress response and HPO axis understanding.
- To clarify glucocorticoid's role in vitellogenin secretion and feeding behavior.
Main Methods:
- Review and synthesis of existing literature on glucocorticoid action in teleosts.
- Analysis of conflicting results from whole-animal and in vitro studies.
- Examination of the interplay between the HPO axis and other endocrine axes.
Main Results:
- Conflicting results exist regarding direct vs. indirect glucocorticoid effects on the HPO axis.
- Glucocorticoids may redirect energy from ovarian growth to support the stress response.
- In vitro studies suggest direct effects on hepatic vitellogenin synthesis and ovarian steroidogenesis, but cellular sites remain unclear.
Conclusions:
- The stress response and glucocorticoid regulation are highly complex in teleosts.
- Glucocorticoid action on ovarian function is intricate, involving interactions with multiple endocrine axes.
- Further research is needed to fully elucidate the cellular mechanisms and in vivo relevance of glucocorticoid actions.
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