Male hypogonadism can be caused by a disease of the
testicles, or an altercation of the pituitary gland, which results in
insufficient production of gonadotrophic hormone. Changes in the pituitary
can be congenital (eg Kallman syndrome) or may be acquired as a result of a
pituitary adenoma (eg prolactinoma, craniopharyngioma) or as a result of
radiation treatment.
In men, hypogonadism causes the symptoms and signs of deficiency of the
hormone androgen. Their effects vary with the development of disability
before or after puberty. Typical effects include the lack of growth of body
hair and beard, soft skin, a high-pitched voice, sexual drive and
performance reduced, underdevelopment of the genitalia and poor muscular
development.
Hypothalamic-pituitary
disease
Hyper-and / or hypo-secretion of hormones or
hypothalamic pituitary is a rare cause of infertility. When this is the
cause of infertility, the results of pro-fertility treatment are often
excellent. Two syndromes are recognized:
Hypergonadotropic hypogonadism
Hypogonadism
Hypergonadotropic hypogonadism
This altercation is characterized by very high
levels of circulating gonadotropins, but the testes do not respond to
stimulation. These findings usually occur in patients with primary
testicular failure. The chances of fertility are remote, but the empirical
hormonal treatment with testosterone is rarely effective.
Hypogonadism In these patients, the secretion of pituitary
gonadotropins is insufficient to stimulate the normal testes. The defect may
be at the level of the pituitary gland itself, or at the hypothalamic level.
A very large number of endocrine disorders, most of them rare, such as
trauma, infections or tumours, can result in levels of gonadotropins absent
or reduced.
Is possible to differentiate between primary failure of pituitary secretion
or pituitary insufficiency secondary to a hypothalamic defect, with reduced
secretion of GnRH. In the case of primary pituitary insufficiency, the
treatment is replacement therapy by administration of exogenous
gonadotropins. When the defect is at the hypothalamus, specific treatment is
by administration of GnRH.
Chromosomal
An abnormal numbers of sex chromosomes may result in
changes in the male reproductive system. For example, infertility often
follows the Klinefelter syndrome. This condition occurs due to a chromosomal
abnormality in which a male subject has one or more extra X chromosomes in
their cells. Klinefelter's syndrome affects about one in every 500 male
children born and the likelihood of a baby having the condition increase
with age of the mother.
Klinefelter's syndrome is almost always associated with azoospermia. The
extra X chromosome appears to have little effect on the structure of the
seminiferous tubules before puberty, but puberty appears progressive and
devastating destruction of the seminiferous epithelium. Some patients with
Klinefelter syndrome, in fact, have significant growth of the testes in
early puberty, followed by a subsequent decrease in size. Also there is an
increase volume of the breasts
There is no cure for Klinefelter syndrome, although hormone therapy can be
used to induce secondary sexual characteristics, such as growth of facial
hair.
Men with an extra Y chromosome have various degrees of spermatogenic
impairment, ranging from normal spermatogenesis to stop spermatogenesis.
There are some other rare chromosomal changes that also result in inability
to produce sperm.
Defects in sperm-egg fusion
It has been shown that additional adhesion molecules are
located on the surface of the oocyte and sperm. These molecules interact and
lead to fusion (fertilization). The function of this system seems to be
important not only for fusion but also for the prevention of polyspermy (the
fertilization of an egg by more than one sperm). Changes in adhesion
molecules on the surface of gametes, or other disabilities that affect
sperm-egg fusion, are recognized causes of infertility
