Maintenance of Homeostasis for Thyroid Hormone in the Adult Rat Brain: Possible Involvement of a Nuclear-Mediated Phenomenon
| Autor: | Angshuman Biswas, Jhuma De, Mitali Pramanik, Samita Kundu, Arun K. Ray, Sumedha Roy |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Male
endocrine system medicine.medical_specialty endocrine system diseases Endocrinology Diabetes and Metabolism Central nervous system Deiodinase Biology Iodide Peroxidase Rats Sprague-Dawley Cellular and Molecular Neuroscience chemistry.chemical_compound Endocrinology Antithyroid Agents Hypothyroidism Internal medicine Cyclic AMP medicine Animals Homeostasis Cyclic adenosine monophosphate Cycloheximide Cell Nucleus Cerebral Cortex Protein Synthesis Inhibitors Endocrine and Autonomic Systems Mechanism (biology) Thyroid Age Factors Adenosine Rats Thyroxine medicine.anatomical_structure chemistry Propylthiouracil Acetylcholinesterase Dactinomycin biology.protein Triiodothyronine Sodium-Potassium-Exchanging ATPase Synaptosomes Hormone medicine.drug |
| Zdroj: | Neuroendocrinology. 86:94-103 |
| ISSN: | 1423-0194 0028-3835 |
| DOI: | 10.1159/000107580 |
| Popis: | During adult-onset peripheral hypothyroidism, the brain maintains normal levels of thyroid hormone for some time through a mechanism of ‘central homeostasis’. Although onset, duration, and termination of such a homeostatic phenomenon have been recently evaluated in rat models, the mechanism behind remains unknown. During our investigation to understand the mechanism further, we injected the protein synthesis blockers actinomycin D and cycloheximide along with propylthiouracil to adult male rats during the days of onset (day 2) and termination (day 20) of the homeostatic mechanism. We evaluated synaptosomal T3 level and neuronal Na+-K+-ATPase and acetylcholinesterase activities along with deiodinase II activity and cyclic adenosine monophosphate level in the cerebral cortex. The results indicated prevalence of unchanged or lower levels of synaptosomal T3 on the 2nd and on the 20th day, respectively. Such a condition has been parallely supported by reflections in cerebrocortical deiodinase II activity and cyclic adenosine monophosphate levels. The activities of cerebrocortical synaptosomal Na+-K+-ATPase and acetylcholinesterase, which are the two important physiological parameters for neuronal function, have been found to be supportive of the involvement of a neuronal protein-mediated factor in the ‘on’ and ‘off’ reactions in central homeostasis during peripheral hypothyroidism. The results of our study indicate that the expression of ‘central thyroid hormone homeostasis’ is a genomic nuclear-mediated mechanism. |
| Databáze: | OpenAIRE |
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