Touching Lives - November 2006
The thyroid gland — the body’s stoker
The thyroid gland is located, roughly speaking, in the bow tie position at the base of the neck, below the voice box. It produces a variety of hormones, of which thyroxine is the most important. Its chemical composition is known and it can now be made synthetically.
The word “hormone” is derived from the Greek word meaning “to excite”, but I much prefer the idea that hormones are chemical messengers sent out by one tissue, usually a gland specially designed for that purpose, to affect the activity of other tissues some distance away.The carrier is of course the bloodstream.
Thyroxine contains iodine; the body cannot make the hormone without this element, however hard it tries. Iodine is normally derived from food and water, but there are extensive parts of the world where the population suffers from iodine deficiency. Derbyshire Neck, or goitre, in Britain was caused by an environmental shortage of iodine, but it is easily avoided by adding small quantities of iodine to food, for instance table salt.
The thyroid gland and its hormones could be described as the stokers of the body, because much of their effect is to control how other tissues metabolise food and nutrients to produce energy. They control the synthesis of protein and the sensitivity of other tissues to adrenaline, another hormone which prepares the body for the ‘fight or flight’ response. Longer-term, the thyroid hormones also control the development and proper differentiation of all cells in the body. Thyroid hormone deficiency during pregnancy may, therefore, affect the brain development of the growing foetus.
Research on this subject is currently being supported by a substantial Action Medical Research grant recently awarded to a team at Birmingham Women’s Hospital and at Birmingham University — turn to page 15 for more details.