Considerations L-thyroxine is measured as having a long half-life, which means that it may take up to 4 to 6 weeks before the medication is able to reach its maximum level of effectiveness.
Along with the more powerful thyroid hormone triiodothyronine (T3 thyroxine affects almost every process in the body, including body temperature, growth, and heart rate. Also known as T4. Last Editorial Review: Back to.
Definition of Thyroxine Thyroxine: A hormone that is made by the thyroid gland and is one of the most important thyroid hormones. Four iodine molecules are attached to the molecular structure of thyroxine.
In each of these situations, serum and tissue triiodothyronine concentrations decrease. This decrease in triiodothyronine production may be a beneficial adaptation to starvation and illness because it reduces the breakdown of protein and slows the use of nutrients for generating heat, thereby maintaining tissue integrity and conserving energy resources.
As a result of this inhibition, serum thyroid hormone concentrations are able to fall toward normal levels. The complex interactions between thyroid hormone and thyrotropin maintain serum thyroid hormone concentrations within narrow limits.
2004). Additionally, some PCBs and their breakdown products double-up on thyroid hormones. First, they can tie up thyroid transport proteins in the blood leaving natural thyroid hormones without an escort. Secondly, the compounds boost certain hormone destroying liver enzymes.
The medication is also prescribed to treat or ward off conditions such as lymphocytic thyroiditis, euthyroid or thyroid goiters and specific types of thyroid cancer. As with other medications, there are a number of potential side effects attributed with its usage.
During fetal life and in infancy this stimulatory activity of triiodothyronine is critically important for normal neural and skeletal growth and development; in both the unborn and the newborn, thyroid deficiency is associated with dwarfism and intellectual disability.
(click image for animation) CREDIT : Tulane/Xavier Center for Bioenvironmental Research. Once made, the thyroid gland releases the hormones into the bloodstream where protein chaperones, called thyroid transport proteins, accompany them to target cells in tissues all over the body.