Estrogen Effects on thyroid Hormone Transport in Fish
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Authors
Apolinski, Lisa R.
Issue Date
1992
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
Much research has focused on understanding the
relationship between thyroid function and reproduction, yet
little knowledge has been obtained on exact mechanisms of
interaction between these two systems in nonmammalian
vertebrates. Although observed steroid effects are possibly
modulated by influences on blood thyroid hormone transport
proteins, information on thyroid hormone binding proteins in
fish is severely limited. The effects of estradiol treatment on
thyroid hormone transport in channel catfish (Ietalurus
punctatus) and red drum (Seiaenops oeellata) were therefore
examined to determine whether estrogen stimulation of
vitellogenin, the yolk protein precursor, influences transport of
thyroid hormones. Effects on availability of thyroid hormone for
uptake into target cells due to estradiol-induced changes in
blood plasma composition were examined by measuring free and
total hormone levels in normal and estrogen-treated fish. Upon
treatment with estradiol, vitellogenin production was
stimulated in both species of fish, but total and free thyroid
hormone levels were not affected by treatment. It was
concluded that low doses of estradiol did result in
vitellogenesis, but did not change levels of thyroid hormone.
This conclusion contrasts with other studies using much higher
doses of estradiol.
Description
v, 37 p.
Citation
Publisher
Kalamazoo College
License
U.S. copyright laws protect this material. Commercial use or distribution of this material is not permitted without prior written permission of the copyright holder.