Changes in Thyroid Hormone Concentrations and Total Contents through Ontogeny in Three Anuran Species: Evidence for Daily Cycles

Three anuran species (Rana perezi, Xenopus laevis,andBufo calamita) of different phylogenetic origins and ecological habitats have been studied during ontogeny with respect to day/night changes in whole-body concentrations and total content of extrathyroidal thyroxine (T4) and triiodothyronine (T3)....

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Bibliographic Details
Published in:General and comparative endocrinology 1997-08, Vol.107 (2), p.240-250
Main Authors: Gancedo, B., Alonso-Gómez, A.L., de Pedro, N., Delgado, M.J., Alonso-Bedate, M.
Format: Article
Language:English
Subjects:
Animals
Bufonidae - embryology
Bufonidae - growth & development
Bufonidae - metabolism
Circadian Rhythm
Larva - metabolism
Metamorphosis, Biological
Ranidae - embryology
Ranidae - growth & development
Ranidae - metabolism
Thyroid Hormones - metabolism
Thyroxine - metabolism
Triiodothyronine - metabolism
Xenopus laevis - embryology
Xenopus laevis - growth & development
Xenopus laevis - metabolism
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Summary:Three anuran species (Rana perezi, Xenopus laevis,andBufo calamita) of different phylogenetic origins and ecological habitats have been studied during ontogeny with respect to day/night changes in whole-body concentrations and total content of extrathyroidal thyroxine (T4) and triiodothyronine (T3). There were no significant day/night changes in thyroid hormones (TH) during embryonic stages. Daily cycles in TH with higher nocturnal values appeared during premetamorphosis inR. pereziandX. laevis.Cyclicity disappears for T3, while it is reversed for T4, in prometamorphicR. pereziandX. laevis.In contrast, there were significantly higher T3(0.74±0.13 ng/g) and T4(2.08±0.54 ng/g) levels at night in prometamorphicB. calamita.Significant daily changes in T3and T4with higher nocturnal values (T3, 788.29±118.38 pg/g; T4, 1.95±0.4 ng/g) were again seen inX. laevisat the end of climax, while inB. calamitalow TH values appeared at early scotophase and there were no significant changes inR. pereziat this time. Similar daily profiles were observed for TH whole-body concentrations and total contents.
ISSN:0016-6480
1095-6840
DOI:10.1006/gcen.1997.6922