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Growth Hormone
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stress can have a direct effect on your brain and pituitary gland, causing reduced GH production. Stress also causes damage to GH receptors and GH resistance. Damaged GH receptors mean that the GH does
not function properly. This is similar to insulin resistance, discussed in
Chapter 3. The difference with GH resistance is that unlike insulin, the
body cannot compensate with heightened GH levels. The pituitary
gland is already too pooped out to keep up with the demand.
The most severe form of GH resistance is known as Laron’s syndrome. This genetic condition is caused by a severe mutation of the GH
receptors. GH levels are very high, but IGF-1 levels are low (the GH
receptor in the liver doesn’t work, and IGF-1 cannot be made). The
result is an individual of very short stature, one who cannot be helped
by treatment with GH. Fortunately, we now know enough to treat such
children with IGF-1, bypassing the GH receptor entirely. Mecasermin
(Increlex) is an IGF-1 medication approved to treat growth failure in
children with severe primary IGF-1 deficiency or GH gene deletion.
AIDS is a condition associated with high-level GH resistance.
Because of this, doctors are now treating AIDS patients with megadoses of GH in an attempt to overcome this resistance. GH therapy
improves muscle mass and muscle strength, but studies have not yet
shown that it can prolong life. There is very limited information on the
long-term safety of and proper dosing for GH in AIDS patients.
GROWTH HORMONE
AND INSULIN
So far we have concentrated on the positive effects of GH. As noted
before, this would seem to be the wonder drug, the hormone to have
if you want to lose weight.
But as we’ve seen before, hormonal balance is critical. If GH levels are not perfect, insulin is adversely affected. Abnormal GH levels,
whether high or low, can cause insulin resistance. GH is a counterinsulin hormone and, when high, can cause the body to boost insulin
production in order to compensate. Low GH causes low muscle mass
and high fat mass, another setup for insulin resistance. Then there’s
outright GH deficiency, which also causes insulin resistance. So either
way, too high or too low, abnormal GH levels cause insulin resistance.
Insulin and GH have a push-pull relationship. When you eat, and
insulin is released from your pancreas a few hours later, there’s a surge