title: Thyroid hormone actions on a cholinergic neuroblastoma cell line (S-20Y).
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.
mesh_terms: D000818:Animals; D002455:Cell Division; D002460:Cell Line; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D007453:Iodide Peroxidase / Q000378:metabolism; D009447:Neuroblastoma / Q000201:enzymology / Q000378:metabolism*; D011988:Receptors, Thyroid Hormone / Q000378:metabolism; D014284:Triiodothyronine / Q000494:pharmacology*
chemical_list: D011988:Receptors, Thyroid Hormone; D014284:Triiodothyronine; D007453:Iodide Peroxidase; D002795:Choline O-Acetyltransferase