Thyroxine: What It Is And Associated Diseases

Thyroid hormones play an important role in cellular metabolism and energy production. One of these hormones is thyroxine, which has specific properties that allow it to perform its function.
Thyroxine: What it is and associated diseases

Thyroxine is one of the most important hormones in the human body. Hormones are a series of substances that are synthesized in the glands, and whose main function is to maintain homeostasis or balance in our organism. Unfortunately, a number of diseases are associated with these drugs.

Most conditions are due to an error in the synthesis or release processes. This will consequently change the concentration in the blood and they will not perform their function properly.

What is thyroxine?

Also known as tetraiodothyronine or T4, thyroxine is a hormone made from iodine, which is synthesized and released from a gland located in the back of the throat. It has a special chemical structure, composed of the condensation of the amino acid tyrosine and the addition of 2 atoms of iodine.

The amount of T4 produced in this gland is much larger than other synthesized hormones, but it is not very biologically active. Several studies have established that thyroxine behaves as a peripheral prohormone, ie that it must be transformed into its active form by enzymatic action.

The hypothalamus and pituitary gland regulate the secretion of tetraiodothyronine. Both structures synthesize substances that are able to stimulate or inhibit the release of T4, depending on the requirements of the organism.

Which gland is responsible for the production of thyroxine?

The thyroid gland is responsible for the production and release of thyroxine in the blood. It is located at the back of the neck, just below the larynx, and in front of the trachea. The anatomy of the thyroid gland is similar to a shield: it consists of two lobes on each side of the trachea, and connected to a central area called the isthmus.

Under normal conditions, this gland weighs about 20 grams and is usually not palpable. The main function is the production of various hormones, among which T4 or thyroxine and T3 or triiodothyronine are the most important.

Specialized structures in the thyroid gland called follicles are responsible for synthesizing thyroid hormones. At the center of these follicles is a colloidal substance that contains everything necessary for hormone production. As such, the colloid contains enzymes, iodine, tyrosine and a special protein: thyroglobulin.

What is thyroxine?  A doctor demonstrating a thyroid model and hormone test.
The thyroid gland has two lobes and a central area that connects them called the isthmus.

What is the function of this hormone?

The main function of thyroid hormones is related to the metabolism and growth of the human body. However, thyroxine is less biologically active and has a longer half-life than triiodothyronine. These properties make T4 the ideal drug to maintain a constant reserve.

In general, triiodothyronine is the active form of thyroid hormones, while thyroxine acts as the plasma reserve. When the body has low levels of T3, various enzymes in the peripheral tissue extract an iodine atom from thyroxine and convert it to its active form.

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