Thyroid hormones (T4 and T3) are produced by the follicular cells of the thyroid gland and are regulated by thyroid-stimulating hormone secreted by the anterior pituitary gland.
How are T3 and T4 formed?
When the level of thyroid hormones (T3 & T4) drops too low, the pituitary gland produces Thyroid Stimulating Hormone (TSH) which stimulates the thyroid gland to produce more hormones. Under the influence of TSH, the thyroid will manufacture and secrete T3 and T4 thereby raising their blood levels.
Where does T3 come from?
T3 is a second thyroid hormone that is produced by the thyroid gland, but also in other tissues through deiodination (enzymatic conversion) of T4. T3 helps maintain muscle control, brain function and development, heart and digestive functions.
What gland produces T3 and T4?
The thyroid gland uses iodine from food to make two thyroid hormones: triiodothyronine (T3) and thyroxine (T4). It also stores these thyroid hormones and releases them as they are needed. The hypothalamus and the pituitary gland, which are located in the brain, help control the thyroid gland.
What is the relationship between T3 and T4?
The thyroid produces a hormone called triiodothyronine, known as T3. It also produces a hormone called thyroxine, known as T4. Together, these hormones regulate your body’s temperature, metabolism, and heart rate.
Why is T4 converted to T3?
Inflammation. When the body is inflamed, due to injury, autoimmune conditions, systemic disease or other factors, type 1 deiodinase (D1) activity is down-regulated. This means the conversion of T4 to T3 in the liver and kidneys is impaired, resulting in a higher T4 to T3 ratio in the blood.
What do T3 and T4 target?
Control of T3 and T4
TSH acts on the thyroid gland and causes the release of T3 and T4 into the blood, where the hormones are carried by proteins to their target tissues. T3 and T4 can act on numerous target tissues, such as the brain, bone, heart and the muscles and carry out the functions described above.
Is T3 made from T4?
About 80% of T3 is formed by the removal of one iodine atom from T4, a process called deiodination. This occurs primarily in the liver and kidney, but T3 is also produced in some, if not all tissues.
What does T3 do to your body?
Triiodothyronine is a thyroid hormone that plays vital roles in the body’s metabolic rate, heart and digestive functions, muscle control, brain development and function, and the maintenance of bones.
Is T3 or T4 more important?
Because T4 is converted into another thyroid hormone called T3 (triiodothyronine), free T4 is the more important hormone to measure. Any changes show up in T4 first. T3 and T4 help to control how your body stores and uses energy (metabolism).
What are the 3 thyroid hormones?
The thyroid gland produces three hormones: Triiodothyronine, also known as T3. Tetraiodothyronine, also called thyroxine or T4. Calcitonin.
How do I control my TSH?
- Radioactive iodine to slow down your thyroid.
- Anti-thyroid medications to prevent it from overproducing hormones.
- Beta blockers to reduce a rapid heart rate caused by high thyroid levels.
- Surgery to remove the thyroid (this is less common)
What is the difference between T3 and T4 thyroid hormones?
T3 denotes the active thyroid hormone whereas the T4 denotes the precursor of the thyroid hormone produced by the thyroid gland. Thus, T3 and T4 are the two forms of thyroid hormone that control metabolism. T3 is known as triiodothyronine while T4 is known as thyroxine.
What should my T3 and T4 levels be?
A normal T3 level might be somewhere between 100 to 200 nanograms per deciliter (ng/dL), while a normal T4 level falls between 5.0 to 12.0 micrograms per deciliter (μg/dL). Free T4, which tests for the amount of T4 that is available in the body, should range between 0.8 to 1.8 nanograms per deciliter (ng/dL).
What is normal TSH level for female?
The normal range of TSH levels in non-pregnant adult women is 0.5 to 5.0 mIU/L. In women, during the menstruation cycle, pregnancy, or after menopause, TSH levels may fall slightly outside the normal range, because of fluctuating levels of estrogen.
Does low T3 cause weight gain?
According to Dr. Kitahara, if someone has low thyroid function, their TSH is high, and the thyroid hormones known as T3 and T4 are low—and weight gain often occurs. If someone has an overactive thyroid or hyperthyroidism, TSH is usually low, the T3 and T4 are high, and weight loss occurs.