Doping with growth hormone, a banned substance in sports, can be detected by particular proteins in the blood, and the detection value improves with simultaneous use of testosterone, according to a new study. The results will be presented Saturday, June 2, at The Endocrine Society’s 89th Annual Meeting in Toronto.

Surveys have shown that growth hormone and testosterone commonly are used together by athletes who cheat in an attempt to improve sports performance, said the study’s lead author, Anne Nelson, PhD, of the Garvan Institute of Medical Research in Sydney, Australia.

“Measurement of defined proteins in the blood, which increase in response to growth hormone, is the basis of one of the most promising tests for growth hormone doping,” said Nelson, project manager of the institute’s Growth Hormone Doping Project.

The Garvan Institute is one of the labs that have been working to develop a blood test for doping with growth hormone, which is difficult to detect. The researchers aimed to determine the usefulness of collagen markers, and whether concurrent abuse of testosterone affects the sensitivity of the test. The study was funded by the World Anti-Doping Agency and the Australian Government Anti-Doping Research Program.

Nelson and her co-workers studied 97 healthy, young adult recreational athletes (33 women and 64 men) and randomly assigned the women to receive a placebo (an inactive substance) or growth hormone for eight weeks. Men received placebo, growth hormone, testosterone or a combination of both drugs for eight weeks. The researchers obtained blood samples before, during and for six weeks after drug administration stopped. They evaluated six protein markers in the blood that increase in response to growth hormone.

All markers increased significantly in response to growth hormone, compared with placebo, and the response was greater in men, Nelson said. For one collagen marker, the response was greater in men who took both growth hormone and testosterone.

“Male athletes who cheat by taking testosterone and growth hormone increase the chance of being caught at growth hormone use if they are given this blood test,” Nelson said.

Athletes may even be caught after they are no longer abusing growth hormone. According to the most recent data, some collagen markers remained increased weeks after growth hormone administration stopped.

Novo Nordisk supplied the growth hormone for this study, and Organon provided testosterone.

# # #