response to 3,3',5-triiodo-L-thyronine

Definition

Target type: biologicalprocess

Any process that results in a change in state or activity of a cell or an organism (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of a 3,3',5-triiodo-L-thyronine stimulus. [GO_REF:0000071, GOC:TermGenie, PMID:21382270]

The biological response to 3,3',5-triiodo-L-thyronine (T3), the active form of thyroid hormone, is a complex and multifaceted process that involves a wide range of cellular and molecular events. It is essential for regulating numerous physiological functions, including metabolism, growth, and development. Here's a detailed description of the process:

1. **T3 Binding to Nuclear Receptors:** T3 enters target cells and binds to thyroid hormone receptors (TRs), which are nuclear transcription factors. TRs are located in the nucleus and are part of the nuclear receptor superfamily. There are two main isoforms of TRs: TRα and TRβ, each with multiple subtypes.

2. **Formation of Heterodimers:** Upon T3 binding, TRs undergo conformational changes that allow them to heterodimerize with retinoid X receptors (RXRs). These heterodimers then bind to specific DNA sequences called thyroid hormone response elements (TREs) located in the promoter regions of target genes.

3. **Regulation of Gene Expression:** The binding of the TR/RXR heterodimer to TREs can either activate or repress gene transcription, depending on the specific gene and the context. T3 binding generally leads to the activation of genes involved in metabolism, growth, and development, while repressing genes involved in energy storage and inflammation.

4. **Metabolic Regulation:** T3 plays a crucial role in regulating metabolism by influencing the expression of genes involved in:
- **Carbohydrate metabolism:** Increasing glucose uptake and utilization, promoting gluconeogenesis, and enhancing insulin sensitivity.
- **Lipid metabolism:** Stimulating lipolysis, reducing cholesterol synthesis, and increasing fatty acid oxidation.
- **Protein synthesis:** Promoting protein synthesis and growth.

5. **Growth and Development:** T3 is essential for normal growth and development, particularly during fetal and neonatal periods. It regulates the growth and differentiation of various tissues and organs, including the brain, bones, and muscles.

6. **Cardiovascular Function:** T3 influences heart rate, contractility, and blood pressure. It increases basal metabolic rate, which leads to increased oxygen consumption and cardiac output.

7. **Other Physiological Effects:** T3 also plays a role in:
- **Neurological function:** Regulating brain development, synapse formation, and cognitive function.
- **Immune function:** Modulating immune cell development and function.
- **Thermoregulation:** Maintaining body temperature by increasing heat production.

8. **Disorders of Thyroid Hormone Function:** Imbalances in thyroid hormone levels can lead to various disorders, including:
- **Hypothyroidism:** Deficiency of thyroid hormone, causing slow metabolism, weight gain, fatigue, and other symptoms.
- **Hyperthyroidism:** Excess of thyroid hormone, causing increased metabolism, weight loss, anxiety, and other symptoms.

The response to T3 is a complex process involving multiple signaling pathways and regulatory mechanisms. It is a crucial aspect of maintaining homeostasis and regulating a wide range of physiological functions. Understanding the mechanisms of T3 action is important for diagnosing and treating thyroid disorders and for developing therapeutic strategies targeting thyroid hormone signaling pathways.'
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Proteins (1)

Compounds (18)