How can pituitary conditions affect fertility?
The functions of the testes are controlled by the Gonadotrophins which travel via the bloodstream to the testes.
Luteinizing hormone(LH) acts on specialised cells within the testes and stimulates release of the male sex hormone, testosterone. Follicle-stimulating hormone(FSH)acts on a separate population of cells within the testes to stimulate the production of sperm.
During puberty testosterone is essential for growth, increasing muscle bulk, development of the penis and for male pattern hair growth. In adult life it is important in maintaining the strength of your muscles and bones, improves general well-being and energy levels and is intricately involved in both your normal sex drive (libido) and erections. Lack of the male sex hormone, testosterone, is termed Hypogonadism.
What are the effects of a lack of male hormones?
Anything that affects the normal functioning of the testes can cause hypogonadism and sub-fertility. In this section we are concerned with problems caused by the lack of stimulation of the testes by the pituitary hormones LH and FSH. If the pituitary gland does not produce enough or any gonadotrophin hormones, this can affect fertility in men because:
- Reduced production of FSH will affect the numbers of sperm produced
- Reduced production of LH will affect the production of testosterone.
The normal function of the pituitary gland is most commonly disrupted by the presence of a pituitary tumour. Please be assured that these are benign tumours and not cancerous.
Pituitary tumours are actually swellings in the pituitary -as they grow they may destroy the cells in the pituitary that produce hormones including the gonadotrophins. Treatment to reduce or remove a pituitary tumour, using surgery or radiotherapy, may also affect the pituitary gland’s ability to produce these hormones.
Release of gonadotrophins from the pituitary is also absent in Kallmann’s Syndrome, a rare genetic syndrome frequently associated with absence of the sense of smell (anosmia). In Kallmann’s Syndrome the hypothalamusfails to release GnRH. The lack of stimulation of the pituitary by GnRH means that the pituitary in turn does not release LH and FSH.
What are the effects of a lack of LH and FSH
- Sub-fertility: In order for fertilisation to occur, semen must contain sufficient sperm which must be active and healthy. A normal sperm concentration is considered to be more than 20 million per ml. Fertilisation becomes less likely as the sperm concentration falls progressively below this level.
- Sexual function: Testosterone is an essential male hormone and is needed for the normal interest in sexual activity (libido) and helps erections to happen.
- Other effects: Hypogonadism affects more than sexual function and reproduction, important as these are. Other effects can include lack of energy, depression, loss of body and facial hair, muscular weakness and, in the long-term, Osteoporosis (the thinning of the bones). In some men a lack of testosterone can also cause Gynaecomastia (increased breast tissue).
When hypogonadism occurs during childhood or adolescence, puberty will not progress. As Kallmann’s Syndrome is present before birth it may also be associated with micropenis and undescended testes.
On a day-to-day basis, many men will find these effects of hypogonadism at least as important as the effects on fertility and sexual function.
Is the treatment safe?
Hormone replacement therapy can have some side effects, like most medical therapies. Side effects are not common, because the treatments are designed to return your body to ‘normal’ by replacing natural hormones that you are missing. Your doctor will discuss any possible side effects with you and monitor your progress regularly.
What are the benefits?
It is hoped that testosterone replacement therapy will improve your sexual function, libido and emotional stability. Your energy and physical stamina will increase and your physical appearance will change – you will see increased hair growth and a more ‘masculine’ body shape. Longer-term benefits include changes in skin texture and a decreased risk of osteoporosis and depression. Replacing the gonadotrophin with hCG/hMG will increase your sperm production and thus improve your fertility. It will also increase your production of testosterone, which will have the same benefits as taking testosterone replacement itself.
What are the possible side effects?
The most common side effects with hormone replacement therapy are local reactions. If you are receiving replacement hormones by intramuscular injections, there may be skin redness, swelling and bruising. Implants may work their way out of the insertion site or cause local infections. Other side effects due to hormone replacement therapy seem to be very rare. Remember, the aim is to restore your body’s normal levels of hormones, not to turn you into Superman! Testosterone replacement very rarely leads to aggressive behaviour in men and this is more common if the individual has never before had normal hormone levels.
How long will I need to take the treatment?
If your pituitary gland is missing or irreversibly damaged, you will need to replace testosterone for the rest of your life. As you get older, the amount of testosterone that you are given may decrease – testosterone levels normally fall in men as they get older. Gonadotrophin replacement is only needed if you wish to have a child – once this has been achieved you should discuss your treatment options with your doctor. Gonadotrophin injections are given until sufficient sperm is present in the ejaculate which may take up to two years. Sperm can also be frozen for future use.
How often do I have to take this treatment?
The gels are applied on a daily basis. Implants are replaced every three to six months. Testosterone injections have generally been given every two to three weeks, however the new long-acting formulation may require injections only every three months – your doctor will work out exactly how often you need them. Gonadotrophin replacement injections are given two or three times every week – it may be necessary to combine two different types of preparation to achieve adequate sperm production.
Will other people notice the therapy?
The testosterone implants themselves should not be obvious once the small incision heals, although implant scars may be visible when clothing is removed, particularly after a long course of testosterone replacement therapy through implants. Other preparations are not visible to other people.
What kind of tests will I need once I am taking the hormones?
Whichever type of testosterone replacement therapy you take, you will need to have your levels of testosterone measured a few weeks after you begin in order to check that you are getting the right amount of hormone. This will involve giving a blood sample. It may be necessary to repeat this blood test at intervals. Improvements in symptoms such as your sex drive, impotence and growth of body hair will also show that the testosterone treatment is working. You will need examination of your prostate gland usually by your GP at least once a year as long as you remain on testosterone as well as a prostate blood test called PSA. In order to monitor how you are responding to gonadotrophin replacement, your doctor will need to check semen samples to see if your sperm count has risen.
Am I at greater risk of developing prostate cancer if I am taking the hormones?
Doctors will want to check older men (over 40 years of age) for prostate cancer replacement may promote growth of pre-existing cancer. The development of prostate cancer is no more frequent in men on testosterone replacement than in men whose testosterone is derived from normally functioning testes.
Is the treatment painful?
Intramuscular injections may be painful, especially after you have been injecting for some time. The testosterone implants are given using a local anaesthetic – there may be some pain for a few days until the incision heals. Gels are a relatively pain free option – though you may experience some local itching or irritation.
Can I use this therapy myself or do I need to see the doctor each time?
Some men find that they can give themselves intramuscular injections or their partner may be happy to give them. Otherwise you will need to visit your GP’s surgery for these injections. Implants are inserted at the hospital outpatient department. Gels are the simplest methods of taking testosterone because you can apply them yourself.
How do I store my medicines?
All methods of testosterone replacement treatment can be stored at normal room temperature (up to 25ºC).
Will this treatment affect my future children?
Gonadotrophin therapy (injections to replace the pituitary gonadotrophin hormones, LH and FSH – see previous section “Restoring fertility using gonadotrophin replacement therapy”) is designed to allow your body to produce normal sperm and to enable you to have normal sexual activity. It should not affect the quality of your sperm. Once your partner has conceived, the pregnancy should proceed like any other pregnancy and there is no reason why it should not result in a normal, healthy baby. Testosterone therapy alone will not induce sperm production, and therefore will not improve your chance of conceiving a child.
Is a pituitary tumour hereditary?
Only in very exceptional cases; less than 1%.