Definition

Noun: 1. Any of several closely related compounds produced by the thyroid gland that regulate metabolic activity: Thyroid hormones are iodine-containing hormones, primarily thyroxine (T4) and triiodothyronine (T3), which are secreted by the thyroid gland into the bloodstream. They are essential for regulating the body's metabolic rate, heart and digestive function, muscle control, brain development, and bone maintenance.

Usage Examples

• Noun:
  • The doctor ordered a blood test to check her thyroid hormone levels.
  • Thyroid hormone replacement therapy is common for patients with an underactive thyroid.
  • The production of thyroid hormone depends on an adequate intake of iodine from the diet.

Advanced Usage

• "Thyroid hormone synthesis": The process by which the thyroid gland produces thyroid hormones from iodine and the amino acid tyrosine.
  • A defect in thyroid hormone synthesis can lead to congenital hypothyroidism.
• "Thyroid hormone receptor": A protein within cells that binds to thyroid hormones, allowing them to exert their effects.
  • Mutations in the thyroid hormone receptor gene can cause resistance to thyroid hormone.

Variants and Related Words

• Thyroxine (T4) (n): The primary hormone produced by the thyroid gland; it is a precursor to the more active form, T3.
• Triiodothyronine (T3) (n): The more metabolically active form of thyroid hormone.
• Calcitonin (n): Another hormone produced by the thyroid gland, involved in calcium regulation, but it is not classified as a thyroid hormone in the metabolic sense.
• TSH (Thyroid-Stimulating Hormone) (n): A hormone from the pituitary gland that stimulates the thyroid to produce thyroid hormones.

Synonyms

• Thyroxine (specifically for T4)
• Triiodothyronine (specifically for T3)

Related Phrases

• Thyroid hormone imbalance: A condition where thyroid hormone levels are too high (hyperthyroidism) or too low (hypothyroidism).
  • Symptoms of fatigue and weight gain may indicate a thyroid hormone imbalance.
• Thyroid hormone resistance: A condition where the body's tissues do not respond properly to thyroid hormones.
  • The patient had elevated thyroid hormone levels but no symptoms of hyperthyroidism, suggesting thyroid hormone resistance.

Noun

1. any of several closely related compounds that are produced by the thyroid gland and are active metabolically