Excerpts of a bestseller

ciobl

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quoted by Dr shippen:

The Hormones as a Team

I know this wide spectrum of important hormones sounds fairly complicated. You might well wonder how the body can sort out their overlapping functions and cause them to work together.

By and large, the body does a superlative job. Your metabolism in tune, functioning well, is like a symphony orchestra with all the musicians playing harmoniously together, joined in one happy purpose.

Scientists now believe that the orchestra conductor, the force responsible for controlling the instruments and forging unity out of what could easily be chaos, is the pituitary gland and its related control center, the hypothalamus. The pituitary, a small organ at the base of your brain, is hidden and protected in the middle of the head. Weighing in at less than a gram (one-fortieth of an ounce), it is connected by a thin stalk to the hypothalamus, which is the lowermost part of the

brain itself. The two glands are so closely interconnected that, for practical purposes, they can hardly be thought of separately.

These master glands are the overlords of your hormone empire. They send hormonal messengers to the other glands, bearing precise directions for appropriate secretions of all the hormones we’ve been talking about. Actually, the pituitary sends the messengers, and the hypothalamus tells it what to send. For instance, by means of a hormone called ACTH (adrenal cortical stimulating hormone), the pituitary governs the output of specific adrenal cortical hormones by the adrenal gland. In a similar fashion, it directs the production of the sex hormones through pituitary controlling hormones called gonadotrophins (-trophic means to stimulate the growth of ). All the other endocrine glands we’ve discussed also receive peremptory messages from the control team in the brain.

If, as a result of these communications, the quantities of hormones and the timing of their release are ideally suited to your needs then the result will be optimal physical and mental performance. The orchestra is playing your tune. You know it, you feel it throughout the course of every restful night and energetic day. You’re really living.

In contrast to this happy picture, illness or aging may eventually appear. Then, the music loses harmony. A wrong note is struck first here, and then there, and soon, it sometimes seems, almost everywhere. Aging is a breakdown in the perfect music of youth. Something has changed. The stresses of life have upset the woodwinds, or some genetic inheritance slowly working its way to the surface has thrown the horns into disorder. Perhaps some viral or bacterial onslaught has literally damaged the quality of the instruments.

Most commonly, however---even in the absence of disease---the endocrine glands lose the capacity to manufacture their hormones in the quantities necessary for playing the beautiful music of youth. And when the balance and quantity of your hormones is not ideal, your body begins striking dreadfully sour notes. This is basic medicine, though often overlooked.

It’s also possible---as we’ll see in a moment---for the control glands, the hypothalamus and the pituitary, to lose their capacity to send the proper instructions. For most of our hormone systems, this seems to be less common than a failing productive capacity. That may not be true, however, in the case of testosterone.

Before we proceed to testosterone, let’s not forget to mention one other hormone that shares many characteristics with it. I’m referring to human growth hormone (HGH), an extremely important product of the pituitary gland. Human growth hormone is necessary for the normal growth of children and, until HGH replacement became possible, children who were deficient in it reached maturity as dwarfs. Because of its name and its known function in young people, it was assumed that HGH was not particularly important in adults. We now know that HGH is one of the body’s main maintenance and repair hormones and that the sizable loss of it that occurs as we age can have serious effects on health, leading---among many other things---to weakness, frailty, and diminished immune function. In the last few years, more and more people have been taking HGH as an anti-aging replacement medicine, and the results have frequently been impressive.
 
Testosterone in Men: Two Ways to Fall
We don’t actually know why testosterone declines, but we certainly know how it declines. There are two commonly recognized endocrine disorders that can cause a man to have low blood levels of testosterone. We’re going to discuss these right now, but, in the next chapter, we’ll consider a third type of testosterone disorder that doesn’t necessarily involve declining levels of the hormone and whose significance has consequently been wildly underrated. This is what you’ll come to know as metabolic andropause, and it may be even more important than a straightforward testosterone deficiency.

The two well-recognized types of deficiency are classically known as primary and secondary hypogonadism--- hypogonadism is simply a term referring to underactivity of the sexual organs or gonads. (Hypo- is a term in medicine that always means low, just as hyper- means high---therefore, hypogonadal means low gonadal function.) Hypogonadic men are producing smaller than normal amounts of testosterone in their testicles resulting in deficient blood levels of the hormone. This can be happening because the testicular Leydig cells have lost the capacity to secrete the hormone at youthful levels (primary hypogonadism). Alternatively, the Leydig cell capacity may be unimpaired, but the control glands in the brain are not asking them to use that capacity. The pituitary ought to be dispatching hormonal messengers with stern demands for more testosterone. For some reason these peremptory requests are not being sent often enough or hard enough. That’s secondary hypogonadism.

Let’s consider how the system works and what goes wrong when it goes awry.


Isn’t Anyone in Charge Here?
To regulate any aspect of the body’s functioning, the brain has to know what’s going on. The hypothalamus is the knowledgeable portion of the hypothalamus/pituitary team. It has sensors that detect circulating blood levels of the many specific hormones that the pituitary controls. Acting like a rheostat, it sends messages to the pituitary telling it to turn production by the lower endocrine centers up or down as needed. The system is extremely clever, and, in young people, it almost invariably hums along as smoothly as a high-quality Swiss timepiece.

In the case of testosterone, when the hypothalamus detects that levels are not as high as they ought to be, it sends brief bursts of a hormone called GnRH (gonadotrophin-releasing hormone) to the pituitary. This stimulates the pituitary to secrete LH (luteinizing hormone) and FSH (follicle-stimulating hormone) at about hourly intervals.

LH and FSH are referred to collectively as the gonadotrophins, meaning hormones that exert an influence on the sex glands. These gonadotrophins stimulate the Leydig cells in the testicles to manufacture testosterone. The whole production process is regulated by what scientists call a feedback system. This means that the hypothalamus monitors the levels of testosterone in the blood, and, if those levels rise too high, the hypothalamus down-regulates its signals to the pituitary. The pituitary then slows its secretions of gonadotrophins and less testosterone is produced for a while, until finally the hypothalamus decides the system needs upregulating.
 
Tired Gland
So, what has happened to this economical and efficient system when a man’s testosterone levels are too low? In the case of primary hypogonadism, the problem is in the testicles themselves. The Leydig cells have lost a measure of their natural capacity to secrete the hormone. When this occurs, the hypothalamus notices that not enough testosterone is being produced and tells the pituitary to pump out more LH and FSH to stimulate the Leydig cells. But this stimulation is to no avail. Generally speaking, if blood tests are done in such a situation, it will be found that levels of the gonadotrophins are unusually high, indicating an ongoing effort by the pituitary and the hypothalamus to stimulate activity. To an endocrinologist, high gonadotrophins combined with low testosterone spell out classical testicular failure.

Secondary hypogonadism is a condition in which disorders of the hypothalamus or the pituitary disorders cripple their secretion of the gonadotrophins. In the relative (or complete) absence of these hormonal messengers, the testicles lower (or halt) their production of testosterone even though the still healthy and efficient Leydig cells would be perfectly capable of producing it if proper stimulation were provided.

In my experience, secondary hypogonadism is the more common cause of testosterone deficiency in middle-aged men. Often it’s not clear what the source of this defect in the hormonal system is. Some form of vascular damage may interrupt the pathways leading from the hypothalamus to the pituitary. Severe viral infections or autoimmune disease may cause damage to these central nervous system endocrine glands. There may be not-yet-discovered drug interactions that cause damage and, in some cases, nutritional deficiencies may be implicated.

The attractive thing about secondary hypogonadism is that when it occurs it is usually treatable. There is a hormone called chorionic gonadotrophin (CG) that is very similar in molecular function to LH, which we will discuss in more detail in Chapter 13. Generally speaking, CG is entirely effective at jump-starting the quiescent testes.

Teddy B., who came to see me because, in his words, "I’m feeling crappy," is a good illustration of what occurs. Teddy is a hard-working fifty-two-year-old businessman who wondered where his energy went. I did lab tests and discovered that his testosterone was 272 ng/dl---off the scales by any standard. His levels of FSH and LH were low, which suggested that the problem lay with his central control panel. Requests for more testosterone simply weren’t being sent down.

I tried him on chorionic gonadotrophin, and one month later his testosterone was 1114 ng/dl, which is a little bit off the scales at the high end. Teddy’s fatigue was going away in a rush, but he did feel slightly irritable with almost an excess of manic energy. We adjusted his dose down from three times a week to twice, his testosterone went down into the 800s, and Teddy felt just fine, just like his old, high-energy self. It was a perfect case of secondary hypogonadism, hormonally adjusted.

Such successes are exciting, but it has been my experience that the most significant form of male menopause is not caused by a deficiency of testosterone (whether primary or secondary) but by a significantly more complicated form of hormone disorder.
 
The Testosterone Syndrome ( ISBN 0-87131-829-6) by Dr. Eugene Shippen and William Fryer.

any major bookstore might have it, including amazon, barnes and noble, borders.
 
It has been out for several years. Some of the stuff in it is outdated, but still worth the read....
 
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