Two University of Queensland researchers have helped develop the first known detection test for growth hormone abuse in athletes.
Their discovery, as part of an international collaboration, represents a major breakthrough in the battle against performance-enhancing drugs.
Professor Ross Cuneo and Senior Research Scientist Jennifer Wallace, in the Medicine Department's Metabolic Research Unit at Princess Alexandra Hospital, said the new test was highly specific and sensitive and required only a drop of blood.
The researchers have been investigating growth hormone's role in the body and uses for different medical conditions for 10 years.
In 1990, Dr Cuneo made a world-first discovery that growth hormone taken in sufficient quantities increased muscle mass, reduced body fat mass and increased athletic performance among adults with growth hormone deficiency. Previously, the hormone was thought to have little or no effect in adults.
These findings are believed to form the rationale behind the recent problem of growth hormone abuse in sport.
Suspicion of growth hormone doping by elite athletes has led to the International Olympic Committee and the European Union funding a $3 million research project to develop a detection method for abuse of the hormone.
The project is led by Professor Peter Sonksen at St Thomas' Hospital in London and involves growth hormone researchers in Australia, England, Denmark, Sweden, Italy, Germany and Switzerland.
The Australian researchers are Dr Cuneo and Ms Wallace in Brisbane and head of the Department of Molecular Medicine at the University of Sydney Professor Rob Baxter.
A review of growth hormone regulation and its role in sport, published by the Brisbane researchers, assisted in the design of the large multinational study.
Ms Wallace said team members were optimistic the new test would be in place by the 2000 Olympic Games.
She said the researchers had used their considerable scientific and medical knowledge to rid sport of growth hormone abuse and stop "clean" athletes from experiencing demoralisation at having to compete against athletes known to be using performance enhancing drugs such as growth hormone.
Injected growth hormone is very difficult to detect in the human body because it is also produced naturally. This detection problem is compounded by the fact that humans produce the hormone in pulses and it is found at higher levels following exercise.
Ms Wallace's research has focused on the changes in an athlete's body following controlled injection with growth hormone.
Her work detected several potential markers for the substance in the blood and urine of athletes and defined the effects of exercise on these markers. "These preliminary studies have helped to define markers which may be useful to detect growth hormone abuse, and how these changed following exercise," she said.
This work was done in England as well as in conjunction with Professor Baxter at Sydney's Royal North Shore Hospital. Professor Baxter is a world leader in the molecular signalling system that forms part of the body's growth hormone system.
Director of the Kolling Institute of Medical Research at the Hospital, Professor Baxter has discovered a number of growth factors associated with the growth hormone system. These growth factors play important roles in regulating the body's metabolism and growth. His collaborative support has been vital in the search for suitable markers of growth hormone doping.
Dr Cuneo's previous research has found growth hormone to be beneficial in treating adults with pituitary gland damage sometimes brought about by a brain tumour. The treatment method, involving injections to replace growth hormone production lost through the particular condition, is in use in many countries including England, the United States and New Zealand but is yet to be approved for use in Australia.
In addition, Ms Wallace and Dr Cuneo have examined the role of the growth hormone system in the wasting condition associated with chronic liver diseases such as cirrhosis.
Dr Cuneo said injecting growth hormone, despite the potential benefits in several clinical conditions, may be dangerous whether it was made synthetically or obtained from human sources.
"If excessive doses are used, short term side-effects include fluid retention and pain in the muscles and joints while the long-term side-effects include hypertension, diabetes, irreversible osteoarthritis, enlarged organs, premature heart failure and an increased rate of developing several forms of cancer," Dr Cuneo said.
"Prolonged use of growth hormone from human sources has in the past brought an increased risk of an illness like Mad Cow Disease. Human-pituitary-derived growth hormone is no longer used in clinical practice, but athletes exposed to this old preparation may be at risk."
Growth hormone has been used to treat short children from the 1960s but until the mid-1980s was produced from natural sources in very small quantities. After this time, synthetic manufacturing techniques were perfected and a thriving black market developed.
Dr Cuneo said growth hormone was extremely expensive, even when purchased as a legitimate pharmaceutical. Black market costs might exceed the legal cost by a factor of 10, he said. Injecting growth hormone could cost an athlete more than $30,000 per year, he said.
Both Dr Cuneo and Ms Wallace have a keen personal interest in sport. The husband and wife team are marathon runners. Dr Cuneo's father John won a gold medal in the 1972 Olympic Games for sailing Dragon class while his mother Joy was Queensland's squash champion in the 1950s.
For more information, contact Dr Cuneo (telephone 07 3240 5316 or 07 3206 2206 after hours), Ms Wallace (telephone 07 3240 5363 or 07 3206 2206 after hours) or Professor Baxter (telephone 02 9926 8486).
