Effects of fasting and metabolic hormones on the reproductive axis of coho salmon, Oncorhynchus kisutch
Baker, D.M.; Davies, B.; Pierce, A.L.; Dickhoff, W.W.; Swanson, P. (2000). Effects of fasting and metabolic hormones on the reproductive axis of coho salmon, Oncorhynchus kisutch, in: Norberg, B. et al. (Ed.) Proceedings of the 6th International Symposium on the Reproductive Physiology of Fish, Bergen, Norway, July 4-9, 1999. pp. 478-480
In: Norberg, B. et al. (2000). Proceedings of the 6th International Symposium on the Reproductive Physiology of Fish, Bergen, Norway, July 4-9, 1999. International Symposium on the Reproductive Physiology of Fish, 6. Department of Fisheries and Marine Biology, University of Bergen: Bergen. ISBN 82-7461-048-2. 499 pp., more
In: International Symposium on the Reproductive Physiology of Fish. Museo Nacional de Ciencias Naturales. , more
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| Authors | | Top |
- Baker, D.M.
- Davies, B.
- Pierce, A.L.
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- Dickhoff, W.W.
- Swanson, P.
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| Abstract |
To investigate the proximate mechanisms by which energy stores may influence reproductive maturation in salmonids, we have conducted both in vivo and in vitro experiments in immature coho salmon. In a study of the effects of fasting on the reproductive axis one year prior to time of expected maturation, we found that pituitary content of FSH dramatically increased in fed fish throughout the 8-week trial, but increased only moderately in fasted fish. Gonad weights increased in both fed females and males, but increased only slightly in fasted females, and decreased in fasted males. To test whether growth factors directly stimulate gonadotrope function, we tested the effects of IGF-I and insulin on FSH levels in long-term dispersed pituitary cell culture. IGF-I strongly increased intracellular levels of FSH and GnRH-induced FSH release, whereas insulin had moderate effects. |
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