Human Hormones

Thyroxine (T4) and Triiodothyronine (T3) are hormones found in the human body. Both are secreted by the thyroid gland, and both are classified as anime hormones.
Secretion and Production

The production of the thyroid hormones begins when thyroid-gland cells uptake inorganic iodide from the bloodstream. The inorganic iodide is then oxidized and a reaction occurs. The product of this reaction combines with tyrosine to form two hormones that combine to form both T3 and T4. After production, both T3 and T4 are secreted into the bloodstream.

The thyroid hormones increase metabolic rate, affect protein synthesis, and increase the body’s sensitivity to catecholamines. Because thyroid hormones increase metabolic rate and oxygen consumption, impairment of thyroid hormone production results in growth and maturation disturbances. If thyroid hormone impairment occurs during childhood, it can result in dwarfism.

Another function of the thyroid hormones is control of ovary functioning. Impairment of thyroid function in women can cause irregularities of the ovarian cycle. Additionally, the thyroid hormones may have some control in brain development.
Pharmacological Uses

The first chemical synthesis of the thyroid hormones was performed by Charles Robert Harrington and George Barger in 1926. Synthetic forms of both hormones are available in oral supplements. The only common use of the thyroid hormones, currently, is as treatment for hypothyroidism — thyroid hormone deficiency. However, the effects of the thyroid hormones on the human body are still being studies. One proposed use includes as a hypothermia-inducing drug in patients suffering from ischemic shock.