The male reproductive system works in a similar way to the female one. This means that the secretion of particular hormones from the male pituitary gland controls the function of the testes as regards sperm production. The main hormone produced by the testes is testosterone. Low testosterone levels can lead to loss of libido and to sexual dysfunction generally. In general, measuring the hormones in a man's blood is recommended when semen analyses show a low sperm count or low motility, or when there is sexual dysfunction.
When the semen analysis is abnormal
If the semen analysis is abnormal, hormone testing in the man can tell us whether there is adequate sperm production in the testes, and whether the reason for severe oligospermia or possible azoospermia is obstruction of the tubules that carry sperm from the testes to the urethra (obstructive or non-obstructive oligospermia/azoospermia). This knowledge is extremely important, because sometimes we may need to retrieve sperm from the testes, and normal hormone results reassure us that sperm will indeed be found at testicular biopsy. The main hormones tested in men are FSH (follicle-stimulating hormone) and LH (luteinizing hormone). If the levels of these hormones are unusually high, there is a strong chance that no sperm is being produced by the testes and that sperm retrieval will be unsuccessful. In addition, in some cases there is inadequate secretion of FSH and/or LH from the brain, leading to an extremely low sperm count or to abnormal sperm production. In these cases, measuring these hormones and giving the corresponding hormones from outside restores testicular function and essentially solves the problem of spermatogenesis.
The role of the other glands
The function of the male reproductive system is complex, and hormonal abnormalities in other glands, such as the thyroid, could lead to defective sperm production. It is therefore vital that the appropriate hormone tests are recommended and carried out when investigating and assessing male infertility.