Open AccessJournal Article
Thyroxine and triiodothyronine uptake by the brain of chickens.
P. Rudas,Tibor Bartha +1 more
TLDR
The characteristics of the inhibition of the uptake of labelled hormones by non-labelled iodothyronines speak in favour of the presence of specific, separate uptake sites for T3 and T4 in the blood-brain barrier of young chickens.Abstract:
The instant uptake of 125-I-labelled triiodothyronine and 125-I-thyroxine by the brain tissue was measured in sham-operated (SH) controls, thyroidectomized (TX) and thyroidectomized plus iodothyronine supplemented (TX+T3 or TX+T4) young chickens. It was found that thyroidectomy significantly increases the uptake of iodothyronines, and iodothyronine supplementation returns the uptake close to sham-operated levels. The characteristics of the inhibition of the uptake of labelled hormones by non-labelled iodothyronines speak in favour of the presence of specific, separate uptake sites for T3 and T4 in the blood-brain barrier of young chickens.read more
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Journal ArticleDOI
The hypothalamic-pituitary-thyroid (HPT) axis in birds and its role in bird development and reproduction.
TL;DR: Thyroid function and its hypothalamic-pituitary-thyroid (HPT) axis control in birds is reviewed with emphasis on the similarities and differences in thyroid function compared to mammals and other vertebrate classes.
Journal ArticleDOI
Avian thyroid development and adaptive plasticity.
TL;DR: This review describes the patterns of precocial and altricial thyroid development, their hypothalamic-pituitary control, extrathyroidal control of hormone activation and deactivation, and target tissue effects during development.
Journal ArticleDOI
Thyroid hormone acts centrally to programme photostimulated male american tree sparrows (Spizella arborea) for vernal and autumnal components of seasonality.
TL;DR: The hypothesis that thyroid hormone acts centrally to programme photostimulated male American tree sparrows for all components of seasonality is supported and the most parsimonious interpretation of the data favours T4 as the tissue‐active thyroid hormone for vernal as well as autumnal events, but does not entirely exclude T3.
Journal ArticleDOI
The dioxin-like PCB 77 but not the ortho-substituted PCB 153 interferes with chicken embryo thyroid hormone homeostasis and delays hatching
Simon Roelens,Veerle Beck,Johan Maervoet,Goele Aerts,Geert Reyns,Paul Schepens,Veerle Darras +6 more
TL;DR: It is concluded that the dioxin-like PCB 77, but not the ortho-substituted PCB 153, can decrease TH availability towards the end of embryonic development and hence disturb the process of hatching.
Journal ArticleDOI
Effects of thyroxine (T4) or triiodothyronine (T3) replacement therapy on the programming of seasonal reproduction and postnuptial molt in thyroidectomized male American tree sparrows (Spizella arborea) exposed to long days
Bryan D. Reinert,Fred E. Wilson +1 more
TL;DR: Results show that subcutaneously administered T3 mimicked T4 imperfectly and suggest either that T3 does not program photostimulated male tree sparrows for photorefractoriness and postnuptial molt, or that T2 does not cross the blood-brain barrier as efficiently as does T4.