Getting A Shot Of Youth

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.

CHART: NOT AVAILABLE

CREDIT: TIME Chart by Joe Lertola

CAPTION: EFFECTS OF HUMAN-GROWTH-HORMONE INJECTIONS IN MEN OVER 60