Thyroid Hormone Actions on a Cholinergic Neuroblastoma Cell Line (S-20Y) |
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Authors: | Marco Chacon Stephen R. Max Judith A. Kirshner J. T. Tildon |
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Affiliation: | Departments of Neurology and Pediatrics, University of Maryland, School of Medicine, Baltimore, Maryland, U.S.A. |
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Abstract: | Thyroid hormone (T3) has a multiplicity of effects on the developing nervous system. We have investigated T3 action using a cholinergic neuroblastoma cell line (S-20Y) as a model. S-20Y contains a nuclear receptor for T3 with binding properties similar to those of other T3 target tissues. In addition, these cells can carry out 5'-deiodination, which is necessary to produce active thyroid hormone in vivo. The enzyme involved in this process appears to be a type I deiodinase, based on its reaction kinetics and its susceptibility to inhibition by propylthiouracil. S-20Y cells maintained in T3-depleted medium showed decreased choline acetyltransferase (ChAT) activity. ChAT activity was restored to the control level in a dose-dependent manner by T3 repletion. Neither cell density nor viability was influenced by the hypothyroid state. The presence of a T3 receptor and the enzyme activity for T3 production, together with an effect of T3 on ChAT activity, demonstrate that S-20Y cells are a target for T3 action and suggest that these cells represent an excellent model system for studies of T3 effects on nervous tissues. |
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Keywords: | Thyroid hormone Cholinergic neuroblastoma cells Deiodinase Choline acetyltransferase |
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