Abstract
TSH, IGF-1 and cellular ras genes have been proposed to function in thyroid cell transformation. Using cultured follicular cells, we demonstrate that TSH, IGF-1 and microinjected activated ras protein individually stimulate DNA synthesis. TSH-stimulated pathways include Gs at the plasma membrane and cyclic AMP response elements in the nucleus. The pathways and nuclear targets of IGF-1 and ras action appear at least partially distinct from those used by TSH.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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8-Bromo Cyclic Adenosine Monophosphate / pharmacology
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Animals
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Cells, Cultured
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Cyclic AMP / metabolism
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Cyclic AMP / pharmacology
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DNA / biosynthesis*
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Enzyme Activation / drug effects
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GTP-Binding Proteins / metabolism
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Insulin-Like Growth Factor I / pharmacology*
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Protein Kinases / metabolism
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Proto-Oncogene Proteins p21(ras) / pharmacology*
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Rats
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Rats, Wistar
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Second Messenger Systems
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Thyroid Gland / drug effects
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Thyroid Gland / metabolism*
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Thyrotropin / pharmacology*
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beta-Galactosidase / metabolism
Substances
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8-Bromo Cyclic Adenosine Monophosphate
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Insulin-Like Growth Factor I
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Thyrotropin
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DNA
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Cyclic AMP
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Protein Kinases
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beta-Galactosidase
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GTP-Binding Proteins
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Proto-Oncogene Proteins p21(ras)