Former baseball slugger Jose Canseco rocked the sports world last week with his personal accounts of steroid abuse in Major League baseball. In the process, Canseco introduced the public to a lesser-known supplement: human growth hormone. GH is gaining notoriety as the latest choice in illegal supplements, favored by athletes because it is difficult to detect and it increases muscle mass. But what exactly is growth hormone?
\In general, growth hormones contribute to the growth of all of the organs of the body,"" said UW-Madison professor of comparative biosciences Norman Wilsman. ""Growth hormone is also important in maintaining normal growth velocities in all bones.""
Growth hormone is a protein produced in the pituitary gland and is essential for human growth. Its production increases as we approach puberty, peaks during adolescence and declines around the age of 20. Production continues to decline for the rest of our lives, but some people are tempted to keep their GH levels artificially high.
Growth hormone is sometimes called the anti-aging drug because it has been linked to increased bone density, tissue repair, faster healing and cell regrowth. As our GH levels decrease with age, we observe the natural symptoms of growing older: we lose stamina, our muscles lose flexibility, our healing slows and we wrinkle.
Athletes have extra incentive to increase their GH level: it helps the body maintain lean body mass and it breaks down fat. It is also undetectable as a supplement; we all have growth hormone in our systems, so a positive GH test cannot be interpreted as a smoking gun for abuse of illegal supplements.
Doctors prescribe GH for kids whose pituitaries do not produce enough GH; not only do GH deficiencies prevent normal growth, but the patients are also at risk of kidney failure and gonad dysfunction. Adults who take growth hormone will also see real anti-aging benefits, but there are potentially deadly consequences to having too much GH.
""The amounts that these athletes take are much, much higher than what we give either children that are growth hormone-deficient, or adults that are growth hormone-deficient,"" said UW-Madison assistant professor of endocrinology Ellen Connor. ""There are some very serious, potentially fatal side effects with giving amounts [of growth hormone] above what the body actually needs. In adults the most serious side effects would be heart failure and death."" It can also cause fluid retention, arthritis and carpal tunnel syndrome, and in severe cases, gigantism, which is excess growth of bone mass and thickening of the skin. It may also have as-yet-undiscovered long-term dangers.
The distribution and sale of human growth hormone is highly regulated and it can only be purchased from approved pharmacies, so athletes may look elsewhere to get it. According to Connor, one of the dangers of purchasing GH outside the U.S. or through the Web is that users cannot be sure of the purity and safety of the samples they get.
""What people are getting over the Internet may not be human growth hormone at all. Some of it may be black-market hormone that they're getting from other countries,"" he said.
But not everyone agrees that the use of growth hormone is dangerous. Canseco argued that growth hormone is such a miracle drug that it should be commonplace. Though he told Mike Wallace of ""60 Minutes"" that steroids and growth hormone are not for everyone, he steadfastly maintained that a responsible regimen of GH supplements could extend a player's career, help him avoid injury and improve his performance.
""I truly believe, because I've experimented with [growth hormone] for so many years, that it can make an average athlete a super athlete. It can make a super athlete incredible. Just legendary,"" Canseco said. Even some scientists agree growth hormone is not necessarily a bad supplement.
""The bottom line is that there are remarkably few serious side effects of growth hormone,"" said Norman Fost, a pediatrics professor at the UW-Madison medical school. ""It can affect glucose metabolism, so if you have a predisposition to diabetes, too much growth hormone could possibly exacerbate that. So there are some metabolic effects, but taken under the supervision of a physician, it's remarkably low-risk. Overall the risks of steroids are also wildly overstated in the press.\
