HEALING THERAPIES NEWSLETTER
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This is the 56th newsletter© (~9,000+
registrants) associated with
<http://www.healingtherapies.info/>www.healingtherapies.info,
the purpose of which is to expand the healing
spectrum of people with physical disabilities,
especially spinal cord dysfunction.
This newsletter specifically discusses
testosterone and testosterone replacement therapy.
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is an instructive book for anyone, with or
without disability.
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TESTOSTERONE
(Adapted from an article appearing in August 2011 PN Magazine)
In recent newsletters, I've discussed the
potential of two female-associated hormones,
estrogen and progesterone, to be neuroprotective
after spinal cord injury. Both inhibit a variety
of neuron-damaging processes that occur after SCI
and, by so doing, may limit neuronal tissue loss
and preserve function. This newsletter will
specifically provide an overview of testosterone
and testosterone replacement therapy (TRT).
Although viewed as the virilizing male hormone,
women also produce small amounts of testosterone.
The hormone is primarily produced by the testes
in men and the ovaries and placenta in women.
Small amounts are also produced by the adrenal
glands. In men, testosterone promotes 1) the
development of reproductive tissue, sex organs,
and secondary sexual characteristics such as body
hair and voice deepening (i.e., androgenic role);
and 2) sexual function, growth of muscle mass and
strength, and bone density (i.e., anabolic
influence). The second benefit also makes
testosterone important in women.
Testosterone Production
Testosterone is synthesized from cholesterol,
which is an essential biochemical building block
for many hormones and nervous-system molecules.
Its production is regulated by the
hypothalamic-pituitary-testicular axis, a
tongue-tying description for a regulatory,
feedback loop used by our bodies to attain
hormonal balance.
Briefly, the hypothalamus, a region of the brain
located above the brain stem, regulates the
release of key hormones by the nearby pituitary
gland, which then stimulates testicular cells to
produce testosterone. However, as testicular
production increases, the elevated testosterone
levels start shutting off the brain's release of
testosterone-stimulating molecules. As a result,
testosterone output decreases (figure). Because
testosterone synthesis is
central-nervous-system-driven process, a major
CNS disruption like SCI can affect testosterone
levels.
Carried via the bloodstream, the
testicular-synthesized testosterone (or its
derivatives) reaches the target tissue, such as
muscle, bone, sex organs, kidney, liver, and
brain. It is then transported into the cells and
interacts with the DNA of specific genes. This
interaction cranks-up gene expression and, in
turn, the tissue products resulting from that
expression - e.g., more muscle, etc. As a simple
analogy, it's like speeding up a manufacturing
assembly line.
Testosterone Levels
Normal testosterone blood levels range from about
300-1,000 and 25-90 nanograms per deciliter in
men and women, respectively (nanogram is
one-billionth of gram (~28 grams/ounce);
deciliter is one-tenth of liter).
Only about two percent of the body's testosterone
is biologically active free testosterone. The
remaining testosterone is either 1) bound to
albumin, a carrier protein in the blood plasma
(yet still bioavailable), or 2) complexed with
sex hormone binding globulin (SHBG) (no longer
bioavailable). To give a better idea of one's
true testosterone status, laboratory assessments
should measure both total and free testosterone.
Low testosterone levels are referred to as
hypogonadism, a condition associated with
osteoporosis (loss of bone density), decreased
lean body mass (i.e., more fat), less strength,
reduced mental acuity and focus, mood changes,
fatigue, less sexual desire, and erectile
dysfunction. As men age, testosterone levels
decline, a process called andropause after middle
age.
In addition to age, various factors contribute to
low testosterone levels. For example, 1)
excessive amounts of the hormone can be converted
into estrogen, 2) as men age or become sick, more
testosterone is taken out of commission by
binding proteins, 3) the pituitary and
hypothalamus may not release sufficient hormones
to adequately stimulate testicular testosterone
production, and 4) the testicles may have lost
their ability to generate testosterone.
Testosterone also can be compromised by various
medications. For example, an elderly relative of
mine was given a drug to treat his prostate
cancer. The drug works by knocking off testicular
testosterone production thereby depriving
hormone-dependent cancers of the testosterone
they need to grow. Unfortunately, eliminating a
key body-strengthening hormone is not innocuous.
In my relative's case, his six-foot, three-inch
frame drastically shriveled due to osteoporosis
and muscle wasting, making me wonder, which was
worse: the cancer or the treatment.
Testosterone Replacement Therapy
Although once the realm of body-building
athletes, many have adopted TRT to mitigate the
consequences of testosterone diminution from
aging or other causes. TRT-related benefits
potentially include less osteoporosis, type-2
diabetes, cardiovascular disease, erectile
dysfunction, depression and anxiety, and
Alzheimer's disease. Although these rejuvenating
benefits sound appealing, one should approach TRT
carefully, weighing the pros and cons relative to
one's unique situation with guidance of a
physician well experienced in the issues involved.
TRT requires ongoing monitoring to manage
potential side effects. Because testosterone
influences many bodily functions, it should be
prudently used. When it comes to TRT, keep in
mind the old margarine commercial: "It's not nice
to fool Mother Nature." Modern medicine is
replete with many examples of drug-related side
effects emerging years after treatment.
A foremost consideration is that TRT should be
viewed as a long-term commitment to not only the
therapy but various medical assessments that
should be carried out on an ongoing basis. TRT
will shut down testicular testosterone
production. By taking testosterone, you will
disrupt the aforementioned
hypothalamic-pituitary-testicular feedback loop
and turn off whatever limited synthesis you had
before treatment. As a result, if you have to
discontinue TRT for any reason, your body will be
generating little testosterone, and your physical
and mental state will reflect this paucity. The
body probably will eventually recover to baseline
levels, but it may take a while.
Testosterone Formulations
TRT has used a variety of formulations.
Oral Agents are quickly absorbed and metabolized
by the liver and may be toxic to this organ.
Intramuscular Injections are commonly used.
Weekly/biweekly injections are often
self-administered. This regimen produces a yo-yo
effect in which testosterone levels peak after
injection and fade until the next injection.
Long-lasting formulations being developed may
minimize the effect. (Cheapest option)
Transdermal Gels are applied daily to skin areas
that minimize accidental transfer to others, i.e.
you don't want to get testosterone on your child
after a hug. Daily use prevents yo-yo effect.
Transdermal Patches: Skin irritation is possible,
and patch visibility may be of concern.
Pellets: Longer-lasting, grain-of-rice-size
pellets are implanted underneath the skin.
Sublingual/Buccal dissolvable tablets are placed
under the tongue (sublingual) or by the gums
(buccal). Because little is swallowed, liver
toxicity is minimized. It requires to be used 2-3
times a day, which may be impractical for many.
Potential Side Effects
TRT should be viewed as a double-edged sword, in
which clear benefits must be balanced against
potential side effects, including the following:
Prostate Health: Testosterone stimulates the
growth of prostate cancer cells. Evidence
suggests that TRT does not cause cancer but can
aggravate it if present. With respect to the
benign prostate enlargement commonly faced by
many aging men, TRT doesn't aggravate the
condition.
Blood Viscosity: TRT stimulates red-blood-cell
production, which may make the blood overly
viscous. This can compromise blood circulation,
predisposing one to high blood pressure and more
strokes and heart attacks. The condition, which
occurs in a small proportion of men, can be
readily resolved by periodic blood donation.
Breast Enlargement: If too much testosterone is
converted to estrogen, men may develop enlarged
breasts. This also occurs in a small proportion
of men and can be treated with estrogen blockers.
Low Sperm: High testosterone levels can inhibit
sperm production. Men who want children often
have to discontinue TRT.
Testicular Atrophy: Long-term TRT can cause the
testicles to shrink, a reversible and treatable
condition.
Moodiness: High-dose testosterone users (i.e.,
like some bodybuilders) may experience manic
episodes.
Acne and Baldness: Because testosterone
derivatives stimulate skin sebaceous gland
secretions, acne can develop. Men already losing
hair may lose more hair.
Conclusion
Part 2 will look at SCI's disruption of
testosterone production and how that disruption
may affect post-injury health and wellness.
Evidence suggests that treatment with
testosterone, an agent known to increase muscle
and bone mass, may lessen functional loss after
injury.
Resource: A good starting-point reference is
Testosterone: A Man's Guide by Nelson Vergel,
available at
<http://www.testosteronewisdom.com/>www.testosteronewisdom.com.
© 2011
<http://www.healingtherapies.info/>www.healingtherapies.info
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