TIME: Almanac 1993/TIME Almanac 1993.iso/time/071690/0716350.000

Text File | 1992-08-28 | 5.4 KB | 118 lines

                                                                                MEDICINE, Page 54

Getting a Shot Of Youth


Human growth hormone may reverse some signs of aging

By ANDREA DORFMAN


    From the fruitless quest for the legendary Fountain of Youth
to the current popularity of plastic surgery and Retin-A face
cream, the search for ways to erase the sags and wrinkles of
aging has never stopped. Now it appears that a partial antidote
to the ravages of time may already lie within the human body.
Last week, researchers at the Medical College of Wisconsin and
the Veterans Affairs Medical Center in Milwaukee reported in
the New England Journal of Medicine that injections of a
naturally occurring substance called human growth hormone can
firm up skin, build muscles and trim fat in elderly men, making
their bodies look up to 20 years younger. While there is no
evidence that the treatment can enable people to live longer,
it may one day help many of the aged appear and feel more
robust.

    HGH apparently reverses some signs of aging by changing the
body's composition. Some 80% of a young adult's body consists
of so-called lean body mass -- muscles, organs and bone -- and
the remaining 20% is made up of fatty, or adipose, tissue. But
after age 30 the muscles begin to atrophy, the skin thins out
and lean body mass is replaced by adipose tissue at an average
rate of 5% a decade. By age 70 the balance between fat and lean
may be fifty-fifty.

    For years it was thought that these changes were inexorable
and irreversible, but it is now clear that they are influenced
by changing levels of HGH. Produced by the pituitary gland at
the base of the brain, the hormone stimulates the growth of
bones and organs in children and helps maintain healthy tissues
in older people.

    HGH levels naturally drop over time; by age 60 about 30% of
men produce little or none of the substance. Although
researchers had long suspected that lower levels of growth
hormone might play a role in the aging process, it was not
until the late 1980s, when a synthetic form of HGH began to be
mass-produced in the laboratory, that enough was available to
test the hypothesis. Until then, nearly the entire supply of
HGH, which was extracted in minuscule amounts from cadavers, was
used to treat children suffering from dwarfism.

    The Wisconsin study, led by Dr. Daniel Rudman, was the first
to test the effects of HGH in healthy elderly patients. The
experiment involved 21 men between the ages of 61 and 81 who
had negligible levels of HGH. Twelve of the men gave themselves
injections of synthetic hormone three times a week for six
months; the others received no treatment. All the subjects
followed a diet of about 15% protein, 50% carbohydrates and 35%
fat but were told not to alter their life-styles, including the
amount they smoked and drank.

    After six months, the men taking HGH felt healthier and more
energetic, almost like the old characters who were rejuvenated
in the movie Cocoon. The group's growth hormone levels rose to
those of men under 40. Fatty tissue decreased nearly 15%, lean
body mass increased 9%, skin grew 7% thicker and some vertebrae
became slightly denser. In several respects, the researchers
say, HGH therapy reversed the consequences of a decade or two
of aging. Men in the control group showed no significant
changes in their physiques.

    The researchers emphasize that their findings are
preliminary and that it is far too early to consider
HGH-replacement therapy for all senior citizens. One reason to
be cautious is that overdoses of growth hormone can cause
diabetes, arthritis, high blood pressure, heart failure and
other side effects. Although none of the men in the Wisconsin
study had these problems, long-term use of HGH might increase
the risk. Other questions that remain to be answered include
the age at which treatment should begin, what the optimal dose
is, whether the changes will disappear if the therapy is
discontinued and whether it is effective in older women. The
high cost of HGH -- about $14,000 for a year's supply -- is a
severe drawback.

    Whatever its potential, HGH-replacement therapy is not a
cure-all for aging. For one thing, cells of the brain, eyes,
ears and elastic tissues such as ligaments and tendons are not
responsive to HGH. "The [Wisconsin] study does demonstrate
clear-cut effects of growth hormone," says Dr. Mary Lee Vance,
a University of Virginia endocrinologist who wrote an editorial
accompanying the report, "but to say it reverses the effects
of aging is an overstatement. It's just one part of the
equation." Other processes that may influence aging include
cumulative tissue damage caused by destructive particles called
free radicals that form within the body, and the inability of
genetic material to repair itself completely after being harmed
by everything from pollutants to cosmic rays.

    While HGH cannot make time stand still, it may help stave
off some of the worst effects of aging, including the muscle
deterioration that leaves many older people unable to climb
stairs or carry groceries. No one yet knows if the larger
muscles that HGH stimulates in the elderly will function as
younger muscles do. But if that turns out to be the case, at
least some of the elderly could get a chance to be more active
and productive in their final years.