Definition of color for English Language Learners. : 1  a quality such as red, blue, green, yellow, etc., that you see when you look at something. : 2  something used to give color to something : a pigment or dye. : 3  the use or combination of colors.
The thyroid hormones, triiodothyronine (T3) and its prohormone, thyroxine (T4), are tyrosine-based hormones produced by the thyroid gland that are primarily responsible for regulation of metabolism. Iodine is necessary for the production of T 3 and T 4.hyroid hormones (T 4 and T 3) are produced by the follicular cells of the thyroid gland and are regulated by TSH made by the thyrotropes of the anterior pituitary gland. The effects of T 4 in vivo are mediated via T 3 (T 4 is converted to T 3 in target tissues). T 3 is 3- to 5- fold more active than T 4.
The thyroid hormone thyroxine is also called T4 and is scientifically known as 3, 5, 3â5,â-tetraiodothyronine. It is a hormone produced by the thyroid gland and is a very important hormone in the body. The function of thyroxine involves the stimulation of oxygen consumption which leads to tissue and cellular metabolism.Along with that, it is used as a biochemical indicator of the functioning of the thyroid gland.hyroxine is also converted by the kidney and the liver and turned to other kinds of hormones. Because it plays such an important role in numerous functions of the body, having too much or too little of the thyroid hormone can cause problems in the body.