MEN'S HEALTH
MALE HYPOGONADISM
AUTHOR Ganesh Rao, MD
INTRODUCTION
In male hypogonadism, the body does not
produce adequate amounts of the male hor-
mone testosterone. Testosterone plays an
important role in masculine growth and de-
velopment during and after puberty. Hypogo-
nadism can lead to the absence of secondary
sex characteristics, erectile dysfunction, loss of
muscle mass, osteopenia, infertility and loss of cognitive functions.
CLASSIFICATION
Primary: Primary hypogonadism happens due to problems from
within the testicles. The most common cause of primary hypogo-
nadism is late-onset hypogonadism that occurs as a consequence of
age. The other causes of primary hypogonadism include Klinefelter
syndrome, undescended testicles, mumps, hemochromatosis, tes-
ticular trauma and chemotherapy.
Secondary: The causes of secondary hypogonadism include
pituitary and hypothalamic disease, HIV/AIDS, medications such
as opiates, radiation to the brain, brain surgery, trauma and brain
tumors.
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LOUISVILLE MEDICINE
PATHOPHYSIOLOGY OF TESTOSTERONE AND
HYPOGONADISM
The hypothalamus releases gonadotrophin releasing hormones
in a pulsatile fashion which stimulates the pituitary gland that in
turn produces luteinizing hormone (LH) and follicle stimulating
hormone (FSH). Luteinizing hormones acts upon the Leydig cells
in the testicle to produce testosterone while the follicle stimulating
hormone acts on the seminiferous tubules to promote spermato-
genesis. Testosterone then slows the release of LH via a negative
feedback mechanism slowing the production of testosterone.
Testosterone production slows as a result of age. Approximately
20% of men in their 50s and increasing numbers of men suffer from
hypogonadism as they age.
SYMPTOMS
The symptoms of hypogonadism are fatigue, sleepiness, erectile
dysfunction, depression, anemia, weight gain and infertility.
SIGNS
On physical exam, the signs include testicular atrophy, gynecomastia
and obesity.