Tyroxín

Tyroxín, also known as L-thyroxine or T4, is a thyroid hormone. It is produced and secreted by the thyroid gland in the neck. Tyroxín plays a crucial role in regulating the body's metabolism, which is the process of converting food into energy. It influences heart rate, body temperature, and the breakdown of carbohydrates, fats, and proteins.

The production of tyroxín is controlled by the pituitary gland, which releases thyroid-stimulating hormone (TSH). TSH signals the thyroid gland to produce and release more or less tyroxín as needed. This forms a feedback loop that helps maintain stable levels of thyroid hormone in the blood.

Tyroxín is essential for normal growth and development, particularly in children. It is vital for brain development and maturation. In adults, it helps maintain energy levels and cognitive function.

Disruptions in tyroxín levels can lead to various health conditions. An underactive thyroid (hypothyroidism) can result in insufficient tyroxín, leading to symptoms like fatigue, weight gain, and feeling cold. An overactive thyroid (hyperthyroidism) produces too much tyroxín, causing symptoms such as rapid heart rate, weight loss, and anxiety.

Tyroxín is also used as a medication to treat hypothyroidism. Synthetic tyroxín, often referred to as levothyroxine, is a common treatment that helps restore normal metabolic function by replacing the hormone the body is not producing adequately.