Expressions like ‘Ah, he’s all hormones,’ or ‘it’s just his hor¬mones’ are common, but what really are these hormones? A hormone is a messenger, a chemical substance that is produced in a gland in one part of the body and then carried by the blood to bring about effects in other parts of the body. It may also produce effects in the organ that makes it. Here we are talking about the male sex hormones and the pituitary hormones that regulate them.
The male sex hormones are called androgens. There are a number of them, but the major player is testosterone, (which we’ve already mentioned) produced in the testes in specialised cells called the Leydig cells. As we noted, cho-lesterol is the basic raw material for testosterone, as well as for all the steroid hormones, which includes all the andro-gens. We’ll talk a little more about a couple of the others later in this chapter.
The output of testosterone by the Leydig cells is regu¬lated by a feedback loop with the pituitary gland, which is a small gland in the brain, situated roughly behind the eyes (in both males and females). This, in turn, is directed by the hypothalamus, another brain area in very close proximity.
Communication between these three is done via several different hormones conveying messages. The hypo-thalamus releases gonadotrophin releasing hormone (GnRH for short) and this tells the pituitary to release luteinising hormone (LH) which in turn stimulates the Leydig cells to produce testosterone. In return, the level of circulating testosterone signals the hypothalamus to turn off or decrease GnRH production until the testosterone levels fall or level out. This is rather like the boss sitting back and having a cuppa when the road gang is working and doing its job, but rising to his feet and yelling when he notices somebody slacking off. We have also provided a simplified diagram for you.
What are the functions of the androgens? The first noticeable effect of testosterone is to cause the testes to descend into the scrotal sac, usually during the last couple of months of intra-uterine life. Testosterone is produced by the male foetus quite early on. Later, the increase in testosterone production at puberty causes the body changes associated with puberty—we’ll talk about this in detail later on in this chapter.
Testosterone affects the distribution of hair on a man, causing the diamond-shaped fan of hair in the pubic area up to the navel, hair on the chest and sometimes back, and yes, contributes to the sparseness of hair up top! Baldness is attributable to a combination of genetic factors (just like your Dad’s) and higher levels of androgens.
Male skin is thicker and typically oilier than that of females—this, too, is due to androgen production. Jim suffered with very oily skin and a lot of acne from age fourteen on—he also began to lose his hair at age 25 and was bald by 30. His wife Marilyn was fond of rubbing his pate and telling one and all that he was the sexiest man she’d ever met! (Certainly there is some evidence that men who lose their hair early have higher levels of testosterone than others—though still within the normal range—and testos¬terone as we shall see is essential for male sex drive so Marilyn may well be right.)
We all know that men have deeper voices than women—testosterone, again!
Testosterone is vitally important for muscle develop¬ment. It is what initially triggers the typical male bulkiness of muscle mass and this is why androgens are being abused by athletes and body builders. Unfortunately, the doses used are often dangerously high and the quality of the drug may make it unfit for human consumption.
Bones benefit from testosterone as well, and testos¬terone is necessary for normal bone growth and strength in men. Indeed, some women are given testosterone, in small doses, as a supplement after menopause when they show bone loss.
Metabolic rate is affected by testosterone—it speeds up all the basic activities and processes of the body’s cells. The blood volume is also increased, as is the number of red blood cells. These effects may also be sought by athletes and body builders, because they enhance athletic performance. Keep in mind that this is illegal and banned by various sports organisations for good reason: it is not a healthy thing to do.
Testosterone and the other androgens also have a mild effect on the balance of water and salts in the body. Under normal circumstances, this is insignificant compared with the effects of the hormones produced by the adrenal gland, but if you abuse androgens, normal may be turned on its head and these effects could be harmful. Yes, testosterone can be prescribed in a therapeutic manner, but this is only after blood levels have been checked and found to be low on at least two samples.
Last but not least, as we’ve already mentioned, testos¬terone gets the blue ribbon for keeping men sexually interested and motivated. Men with low testosterone, for whatever reason, typically have a low sex drive.
However, testosterone production is not the be all and end all—you still wouldn’t produce sperm unless the pituitary gland put out follicle stimulating hormone (FSH), which supports the maturation of sperm in the testes. As you can see, managing the operations of the testes is an exquisitely organised process as complex as air traffic control.
At puberty, some unknown signal gears up the hypothalamus to secrete GnRH in a pulsatile pattern that stimulates the pituitary to release LH and FSH. Why and how it starts to do this some time between the ages of nine and fourteen in most boys is one of life’s mysteries. But it does. We then see a recognisable pattern of development—the pubertal milestones. These are commonly referred to as the Tanner stages of adolescent development.
Boys often have concerns because they may be devel¬oping at different rates from their friends—obviously, if the age at which this all begins ranges from nine to fourteen, you will have boys in the same class at school at various stages of the process. This is quite normal and the average ages given on page 28 are just that—average. Boys should also be assured that the breast development they may see will not be with them all their lives—when the surge of development calms down, the breasts naturally regress, leaving our hero with his manly form.
If your child shows no sign of development by four¬teen or fifteen years of age, just have your doctor check him. Developmental disorders are not very common, but they do occur. If he is one of the early bloomers, remember that his emotional development has not kept pace and he is still a child—so have patience.
What about the other end of the spectrum? Is there a male equivalent to menopause? Strictly speaking, no. Male hormone output does decline with age, but it is a slow and gradual thing, not like the dramatic time that women may go through. And, as many have noted, men can and do father children at very advanced ages. This is not true for women.
Some doctors say that there exists an androgen defi¬ciency syndrome, especially as men age. John Morley MD developed a questionnaire that correlates symptoms with low testosterone levels.
If you answer three or more of these questions posi¬tively, then your serum testosterone should be checked, according to some geriatrics experts. (We know what you’re saying: lots of people of all ages, male and female, would probably answer yes to at least three of these . . .) If low, these experts would supplement you with testosterone. This is controversial, and we still don’t have enough information to indicate whether androgen replacement is in the same category as female hormone replacement.
Table 4.2: Correlation of symptoms with low testosterone
1 Do you have a decrease in sex drive? 2 Do you have lack of energy? 3 Do you have a decrease in strength or endurance? 4 Have you lost height? 5 Do you enjoy life less? 6 Are you sad and/or grumpy? 7 Are your erections weaker? 8 Do you feel your emotions less? 9 Do you fall asleep after dinner?
10 Has your work performance deteriorated?
There are risks to androgen supplementation, and these must be acknowledged. First, as our colleague Dr Cohen cautions, if you are brewing a little prostatic cancer, add¬ing additional testosterone to your system may be like throwing kerosene on a fire. Also, oral testosterone endan-gers your liver; for this reason, most doctors do not prescribe it. It is available by injection or transdermally (through the skin) as a patch or gel.
Testosterone does increase muscle mass and may seem tempting to men who have lost lean mass with ageing. It is not yet known whether testosterone supplementation helps to reverse the decrease in bone mass that is natural to ageing men. And if it does reverse bone loss, does it also reduce fractures? The jury is still out.
Some argue that androgen supplementation will protect men against Alzheimer’s. Maybe…we just don’t have the studies to support this yet.
Besides liver toxicity and possible acceleration of prostate cancer, androgens can cause water retention, and this may pose an increased risk for men with high blood pressure or heart disease. It may also worsen sleep apnoea; it is thought that this happens by causing a thickening of the tissues at the back of the throat.
Probably the biggest controversy raging is about the effect of androgens on blood fats. There are conflicting studies—some showing that HDL (good cholesterol) is reduced by supplementing with androgens, some showing no effect, and some actually indicating a beneficial effect. For now, it is probably best to be cautious and discuss all of this with a trusted doctor who knows you and your particular situation and risks. And if you should at any point be prescribed supplemental androgens, be sure that you are monitored at least every six months.
As mentioned, oral testosterone is not a great idea. Injectable testosterone has been used for decades and is the least expensive route of administration. In recent years, testosterone patches have come on the market and offer a closer match to the physiological pattern of tes¬tosterone release, with peaks early in the day and a diminution toward evening.
Up until now, we’ve pretty much spoken of androgens and testosterone interchangeably. There are, however, a couple of other androgens worthy of some mention, mostly because they are being sold and used as ‘dietary supplements’ and are readily available over the internet and, at least in the United States, in health food stores. These are DHEA and pregnenolone. These are weaker andro¬gens than testosterone and are precursors in the chain of synthesis from cholesterol. Although weaker, they can have many of the same effects as testosterone and pre¬sumably the same ill-effects. In fact, we don’t know enough about the results of using these pharmacologi¬cally. Studies are underway, and there are some diverse and hopeful signs (e.g. that DHEA may increase bone mass in older women) but it is premature as yet to make any ethical claims about these androgens.
Another interesting androgen is dihydrotestosterone, the metabolite of testosterone that is active in the cells. It is at least theorised that topical drugs which block dihydro-testosterone in the scalp cells will allow a rejuvenation of hair growth. In fact, a couple of preparations based on this are now on the market.
Saeed had been buying an expensive drug to grow a little more fuzz on his bald pate. He was delighted when his chemist told him of a cream he could rub in and that it would cost him just a fraction of the current drug. So far, Saeed hasn’t seen much difference…
Your hormonal system is a very finely tuned mechanism. As you can see, it determines your sexual characteristics and thereby your presentation to the world. Our advice to every man would be to take care not to disturb this fine balance by monkeying with illicit androgens.
