Endocrine & Thyroid Glands

Excerpted from
Is Your Thyroid Making You Fat?
By Sanford Siegal, D.O., M.D.

Endocrine Glands

These are rather miniature chemical manufacturing devices positioned at various locations in your body. They are sometimes called ductless glands because they discharge their chemicals (hormones) directly into the bloodstream. Other glands distribute what they produce through small tubes called ducts. An example of the latter are the several sets of salivary glands that are responsible for keeping the inside of your mouth wet.

The thyroid gland is one of the endocrine glands. It sends its products directly into the bloodstream. The pituitary gland and the adrenal glands are other familiar examples of endocrine glands. Each of these glands produces its own unique chemical or chemicals that are needed to affect various processes in the body.

Hormones

The chemicals produced by the endocrine glands are called hormones. Some glands normally produce more than one hormone. These powerful chemicals function as regulators of important body processes. For example, in females, the menstrual cycle is under the control of various hormones secreted by the endocrine glands known as ovaries, as well as by other glands. Repeatedly in this book, I shall refer to the particular hormones that are secreted by the thyroid gland.

Pharmaceutical companies manufacture a variety of hormone look-alikes. Birth-control pills that simulate the functions of the hormones of the ovaries are an example We shall pay particular attention to the attempts that have been made to simulate the thyroid hormones.

Occasionally, the actual hormones are removed from the endocrine glands of animals and are used in human medicine. Before synthetic thyroid hormones were introduced in the 1950s, many people were treated with thyroid hormone that came directly from cows and hogs. Many doctors who had prescribed these could argue that animal-derived thyroid hormone was a quite satisfactory replacement when one's own hormone production was inadequate.

The Thyroid Gland

If we were to rate the various endocrine glands as to relative importance, most authorities would probably put the pituitary gland at the top of the list. Not only does it have a prestigious location, attached to the brain, but it functions largely to regulate other endocrine glands. When its hormones reach other endocrine glands, it often causes those glands to secrete their own hormones. For this reason, the pituitary is often referred to as the Master Gland. One of the glands that is controlled by the pituitary gland is the thyroid gland.

The runner-up in the gland importance competition would undoubtedly be the thyroid gland. The body processes affected by its hormones are very many and diverse. The thyroid gland in turn controls the functions of other glands. The entire endocrine system is a complex interaction of these glands and their hormones. The ultimate purpose is to keep the human machine running properly. When the thyroid gland malfunctions, the entire body is thrown into a chaotic disequilibrium.

Your thyroid gland is located in front of the lower part of your neck. If you press your index finger into the very bottom of your neck in the front, you will find a distinct notch in the bone below. This is the top of a bone called the sternum, and the notch should distinctly cradle your finger. The next two or three inches above the notch to the left and the right is occupied by your thyroid gland. It actually has two parts, one on either side. Don't be concerned if you can't feel it. If the gland is normal in size, it is difficult to find. If it is enlarged, you may feel it; it has the consistency of a ripe peach. If you have considerable fat in this area, you will probably not be able to differentiate the gland from the surrounding fat. It is really not very important that you find your thyroid gland or even feel it. Let's leave that to your doctor. I was obliged to locate it for you. After all, if you're going to read a book about your thyroid gland, you should at least know where it is.

What It Does

The thyroid gland has many functions, but the one I shall give the most attention to is how it controls the rate at which your body uses energy. If that sentence seems somewhat mysterious, I could perhaps clarify it by making substitutions for some of the words. I could replace "the rate at which" with "how fast." "Energy" could be "calories" or even "food." I could use the timeworn analogy of the automobile. Your body is the car and it needs fuel to power the engine. The fuel could come from the outside-in other words, your food. But your food must first be converted into a more refined type of fuel before your engine can utilize it. Your fuel could also come from your storage tank, that layer of fat you would like to be rid of. But even that must be converted into a different form before it can be "burned."

I have said that the thyroid controls how fast the fuel is used. A better explanation is that it controls how much fuel is needed to perform a particular task. In an automobile, the task is to move some passengers from Point A to Point B. Of course, a heavier car or a heavier load will need more fuel. So will a heavier body or one that is performing a more strenuous task. There is a distinction between our objectives when we compare our bodies with our cars.

With automobiles, fuel efficiency is what we strive for. Let's get the most miles per gallon. The auto industry, if we're to believe its spokespeople, is on a constant campaign to improve fuel efficiency, to build cars that will get more miles to the gallon. Strangely enough, those who are overweight would like to achieve the opposite effect. What they would hope for and what they probably don't have is a real gas burner. They want a very inefficient engine that will guzzle fuel. Of course, the fuel you want to waste is your stored fuel, your fat. If there is a day when you're too busy to eat, you will have to dip into your stored fat to supply energy to your engine. You would probably hope that your body would somehow use twice that amount of fuel (energy, calories) that day. At the same time, you would probably wish for your actual car to get twice the mileage from its fuel.

Your thyroid gland in secreting its hormones regulates this use of fuel by your body. If it malfunctions by secreting too little hormone, your body processes slow down. That is another way of saying that you use less fuel. This is one explanation for why some people weigh more than they should. There are other possibilities. It is quite possible that the gland doesn't malfunction but some other mechanism does, but the result is the same. If the targets of the thyroid hormone, the cells that actually carry out the fuel consumption, somehow don't interpret the stimulating effect of the thyroid hormone, fuel consumption doesn't increase. As I've indicated, the effect is the same: less fuel consumption. The solution to the problem is also the same, but how this problem can be solved will come later.

Part of my definition of hypothyroidism is derived from this concept. If the secretion of thyroid hormone isn't sufficient to cause the body to bum calories at a normal rate, it is hypothyroidism. If a "normal" amount of thyroid hormone is secreted but it doesn't achieve the calorie-consuming effect it should, we essentially have the same problem, and I still define it as hypothyroidism. The hypo- prefix to a medical term means "low" or "not enough." The hyper- prefix means just the opposite. There is indeed a hyperthyroidism, a condition in which too many calories are consumed for a given task.

The abnormal burning of calories is the component of hypothyroidism that may generate the most interest, but there are many more signs and symptoms. There are so many and they affect so many diverse bodily systems that it is easy to confuse hypothyroidism with a multitude of other diseases. Even though doctors have nicknamed another disease, syphilis, the "great imitator" because its many manifestations can suggest a variety of other ailments, hypothyroidism may well be an even greater imitator. Presently, I shall go into an exploration of many of the conditions that may accompany hypothyroidism. What often makes the diagnosis difficult for the physician is the fact that although a variety of signs and symptoms is possible, in reality, the usual sufferer displays a relatively small number of them. You can see how confusing the diagnostic task could be. One patient could have three of the signs of hypothyroidism while another has three entirely different signs, yet they both have hypothyroidism. This, coupled with what I believe is a basic flaw in current theory regarding thyroid hormones, often leads to a missed diagnosis.