92-12-11:  Fountain of Youth May be in Pituitary Gland


     Can growth hormone or physical exercise or a combination of
both counteract the decline in muscle strength, stamina and
mobility that accompanies aging? Dr. Michael L. Hartman,
University assistant professor of internal medicine, and a team
of research assistants and exercise physiologists have received
a five-year, $820,000 grant from the National Institute of Aging
to seek an answer. 

     By 2030, when the average baby boomer will be 80 years old,
it is estimated that 14 million people will need help with daily
activities unless disability rates among older people are
reduced, according to the U.S. Bipartisan Commission on
Comprehensive Health Care, commonly referred to as the Pepper
Commission. Concerned by the prospect of a large segment of the
population becoming physically dependent and the resulting
psychological and financial costs (today frailty costs an
estimated $54 billion annually), the National Institute of Aging
is supporting nine clinical studies at medical centers around the
country that will evaluate the effects and safety of using
hormone therapies including growth hormone, estrogen and
testosterone to slow or possibly reverse degenerative changes in
bone density and muscle mass. Growth hormone, which is sometimes
used to treat short stature in children, will  not make adults
grow, but enables certain tissues to maintain their proper size
and structure.

     In recent years medical researchers have linked decreasing
levels of growth hormone, a substance produced by the pituitary
gland, with diminished physical capacity. "There is a steep
decline in the body's production of growth hormone beginning in
the 30s and 40s and continuing into the 50s and 60s. In our
clinical trial, we intend to restore participants' level of
growth hormone to that of younger people in their late 20s by
administering small doses of growth hormone. Side effects can
result, but we will carefully monitor our participants. At the
first sign of feet swelling or an elevation of blood pressure,
we will decrease the dosage," Dr. Hartman said. "If my mother
lived in the area, I would encourage her to join the study," he
added.

     "The U.Va. study is unique, because it is the only study to
focus on the effects of physical exercise on growth hormone
production. Healthy older people will be computer randomized to
one of six treatment groups in which they will receive either
daily growth hormone or placebo injections in a double-blind
fashion and either aerobic training, strength training or no
training for one year," said Dr. Hartman.

     "In the next month or so, we will begin to recruit by
advertising in local newspapers and by visiting senior centers
and retirement communities, like The Colonnades. We will be
seeking 20 to 25 healthy, non-smoking individuals over 60 (there
is no ceiling on age eligibility) who are taking little or no
medication, are not overweight and are not vigorous exercisers.
Each year, we will recruit a new group of men and women;
participants will be paid $500," he said.

     At the beginning of the study participants will undergo five
days of tests at the hospital. After six months they can expect
three days of tests and at the end of the year another five days
of tests. Once a month, they will see Dr. Hartman for an
outpatient checkup.

     Those assigned to the exercise group will participate in
training sessions four days a week; strength training groups will
meet three days a week. At 9 p.m. each night, subjects will
inject themselves at home with growth hormone or a placebo.

     Arthur Weltman, director of the exercise physiology lab in
the Curry School of Education, will supervise the exercise
component of the study. Exercise programs will be individualized
for each of the participants and determined by ratings of
perceived exertion and blood lactate levels.

     In addition to determining the specific effects of growth
hormone distribution and physical training, the study aims to
determine whether one year of physical training will enhance
older individuals' ability to manufacture their own growth
hormone and whether there are gender differences in the responses
to growth hormone distribution and/or physical training,
according to Dr. Hartman.

     Professor Claude Bouchard of Laval University, Quebec, an
international expert in evaluating the distribution of fat in the
human body and its relation to heart disease, will be a
consultant to the U.Va. team. "Studies have indicated that where
people tend to collect fat has a bearing on their risk of heart
disease. One of the reasons men are at greater risk is because
they tend to collect fat around their middle as opposed to their
hips. Intra-abdominal fat poses an even greater risk," Dr.
Hartman said. "Professor Bouchard will instruct our radiologists
on how to use magnetic resonance imaging in tracking fat
distribution. One of the objectives of the study is to test the
hypothesis that growth hormone will affect fat distribution,
thereby reducing the risk of heart disease.

     "Synthetic growth hormone therapy is quite costly -- $30,000
for a year's dosage. Fortunately, Genentech Inc. of San
Francisco, Calif., is donating the hormone for our study. You can
understand, though, why we're excited about the prospects of
exercise triggering growth hormone production. Aside from the
cost, it would be better for the individual to avoid years of
injections. Also, five years from now we might have additional
strategies, such as prescription drugs, to foster the body's
creation of growth hormone," said Dr. Hartman.