T4

T4 or Thyroxine is a hormone produced by the thyroid gland. It is one of the two primary hormones produced by the thyroid, the other being triiodothyronine (T3). T4 is the inactive form of the hormone and is converted into the active form, T3, in the body's cells.

Function

T4 plays a crucial role in the body's metabolism. It helps regulate the rate at which the body uses energy and makes proteins. It also plays a role in the body's growth and development.

Production and Regulation

The production of T4 is regulated by the thyroid-stimulating hormone (TSH), which is produced by the pituitary gland. When the levels of T4 in the blood are low, the pituitary gland releases more TSH, which stimulates the thyroid gland to produce more T4. Conversely, when the levels of T4 in the blood are high, the pituitary gland releases less TSH, reducing the production of T4.

Measurement

The levels of T4 in the blood can be measured using a blood test. This test is often used to diagnose conditions related to the thyroid gland, such as hypothyroidism (low levels of thyroid hormones) and hyperthyroidism (high levels of thyroid hormones).

Disorders

Disorders related to T4 include hypothyroidism and hyperthyroidism. Symptoms of hypothyroidism include fatigue, weight gain, and depression, while symptoms of hyperthyroidism include weight loss, rapid heart rate, and anxiety.

See Also

• Thyroid function tests
• Thyroid disease
• Thyroid hormones

T4 Resources
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