Abstract
Maternal hypothyroidism in the rat compromises alpha-internexin (alpha-IN) expression in early fetal brain. We have therefore examined whether 3,5,3'-triiodothyronine (T3) regulates alpha-IN expression in fetal brain neurons in culture. Cells expressed transcripts encoding T3 nuclear receptor isoforms in a T3-independent manner. alpha-IN protein abundance was increased in cultures treated with 0.1 and 1 nM T3 for 20 h (177 and 185% control, respectively) and in cultures treated with 1 nM T3 for 40 h (131% control). alpha-IN transcript abundance was unaffected by T3 treatment. In conclusion, T3 at a physiological level, stimulates alpha-IN protein, but not mRNA, levels in early differentiating neurons in culture. This supports the hypothesis that maternal thyroid hormone directly regulates early neuronal differentiation.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Blotting, Western
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Brain / cytology
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Carrier Proteins / biosynthesis*
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Cell Differentiation / drug effects
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Cells, Cultured
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DNA / biosynthesis
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DNA / genetics
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Female
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Immunohistochemistry
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Intermediate Filament Proteins
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Male
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Microscopy, Phase-Contrast
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Nerve Tissue Proteins / biosynthesis
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Nerve Tissue Proteins / genetics
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Neurons / drug effects
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Neurons / metabolism*
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Pregnancy
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RNA, Messenger / biosynthesis
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Rats
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Rats, Sprague-Dawley
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Receptors, Thyroid Hormone / biosynthesis
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Reverse Transcriptase Polymerase Chain Reaction
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Thyroid Hormones / pharmacology*
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Triiodothyronine / pharmacology
Substances
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Carrier Proteins
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Intermediate Filament Proteins
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Nerve Tissue Proteins
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RNA, Messenger
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Receptors, Thyroid Hormone
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Thyroid Hormones
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alpha-internexin
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Triiodothyronine
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DNA