T4

Definition

T4, or thyroxine, is a hormone produced by the thyroid gland that plays a crucial role in regulating metabolism and energy levels. It is often measured to assess thyroid function and overall endocrine health.

5 Must Know Facts For Your Next Test

1. T4 is converted into the more active T3 (triiodothyronine) within cells.
2. Normal T4 levels are essential for maintaining metabolic rate, heart function, and digestive health.
3. Hypothyroidism is characterized by low levels of T4, leading to symptoms such as fatigue, weight gain, and depression.
4. Hyperthyroidism involves elevated T4 levels, causing symptoms like rapid heartbeat, weight loss, and anxiety.
5. Dietary iodine is crucial for the synthesis of T4; deficiencies can lead to thyroid dysfunction.

Review Questions

• What role does T4 play in the body’s metabolism?
• How does an imbalance in T4 levels affect overall health?
• Why is dietary iodine important for T4 production?

Related terms

T3: Triiodothyronine (T3) is an active thyroid hormone derived from T4.

Hypothyroidism: A condition where the thyroid gland produces insufficient amounts of thyroid hormones, including T4.

Iodine: An essential mineral necessary for the production of thyroid hormones like T4.