Laboratory testing of male sex hormones

FSH (follicle-stimulating hormone, follicular maturation hormone) is a sex hormone that is produced in the anterior lobe of the pituitary gland. Although FSH and LH are required for normal sexual function in both men and women, the process of excretion in the body is very different for the two sexes.

When may the test be needed?

In case of infertility or suspected infertility, it helps diagnose diseases of the pituitary gland and testicular dysfunction. FSH testing is also part of the examination of men with reduced sperm count.

LH (luteinizing hormone) is a sex hormone that is produced in the anterior lobe of the pituitary gland. In men, it stimulates the production of testosterone in the Leydig cells of the testicles. The secretion of LH is different for the two sexes, but its presence is essential for normal sexual function. The examination of hormone levels aims to detect the possible cause of infertility, to detect abnormalities of the pituitary gland or gonads.

Testosterone is produced by the Leydig cells in the male testicles, and it affects the production of sperm, the behaviour of men, and the condition of their muscles and bones. Testosterone causes secondary sexual characteristics: beard, moustache, hair, and is responsible for the function of the accessory gonads, prostate, and semen.

The most common causes of testosterone decrease in men are: hypogonadism, orchidectomy (testicular removal), oestrogen therapy, Klinefelter syndrome, hypopituitarism, and liver cirrhosis.

What influencing factors might be behind proper testosterone production?

• Overweight
• Insulin resistance
• Type 2 diabetes
• Thyroid dysfunction
• Liver and kidney diseases
• Large amounts of outwardly steroid intake reduce the levels of testosterone that were originally normal, resulting in impaired sperm production.
• Around the age of 50, testosterone levels begin to decline as a natural process of ageing.
• Previous radiotherapy may also affect testosterone levels.

Symptoms of low testosterone levels can be:

• decreasing libido, impotence
• low sperm levels
• decreasing muscle mass, deterioration of general fitness
• mood swings, depression
• a noticeable decrease in concentration
• osteoporosis in old age, loss of fat mass
• thinning of the skin
• breast enlargement

It is important to stress that testosterone supplement should only take place under medical supervision in the form of tablets or injections. In many cases, adequate testosterone levels can be easily restored, but hormone use is not recommended in the long term because it increases the chances of developing cardiovascular disease and sleep apnoea.

Although the hormone prolactin is best known as a pregnancy hormone, it is nevertheless produced in both non-pregnant women and men, but in low amounts. Prolactin levels fluctuate during the day, so we do not get the same value in the morning and evening, and certain medications can increase its levels.

Elevated prolactin levels can in many cases indicate hypothyroidism, which is associated with unpleasant symptoms such as infertility, decreased libido, and hair loss. In rare and more severe cases, pituitary tumours may be suspected, in which case a cranial MRI examination may be performed.

SHBG is a transport protein produced by the liver, which binds and transports 60% of testosterone, dihydrotestosterone, and oestrogen in plasma.

Laboratory diagnostic significance of the test: When measuring low and high testosterone levels, measurement of SHBG is recommended. From the concentration of SHBG and testosterone, the concentration of biologically active hormone (free androgen index) can be calculated.