Blood proteins may be future markers for growth hormone doping

Researchers have found potential new biomarkers for growth hormone, which they say could help the sports community in detecting growth hormone abuse. The results of the animal study will be presented at The Endocrine Society's 90th Annual Meeting in San Francisco. Many athletes are misusing recombinant human growth hormone, a drug intended for people who are growth hormone deficient, because of its supposed ability to decrease fat and increase muscle. However, detection remains a challenge. The growth hormone drug appears only briefly in blood and is identical to the growth hormone that the body naturally makes, said study coauthor John Kopchick, PhD, of Ohio University.

"Variability is a problem with current testing for growth hormone doping," Kopchick said. "It is gender and age-sensitive. We're looking for a test that will give standard results for everyone."

The authors are attempting to identify proteins in the blood that could be biomarkers for growth hormone action. A biomarker is a substance that can be detected in higher-than-normal amounts in the blood, urine, or body tissues and thus could be used for screening.

Kopchick's group injected six male mice with growth hormone once a day for a week and also injected six male mice with saline, to serve as controls. On the eighth day they determined the protein changes in the blood of all mice.

Several proteins or their isoforms (genetic variants or protein sub-populations that are modified differently) greatly increased or decreased in the growth hormone-treated mice, compared with controls, the authors reported. They included transthyretin, clusterin, albumin, and apolipoprotein A-1 (apoA1).

If the results translate to humans, these proteins have the potential to be new biomarkers for growth hormone action, according to Kopchick. Regulatory agencies could use new biomarkers for growth hormone in their attempts to halt the abuse of this drug among athletes, he said.

"Extension of these results to humans is of paramount importance, and these studies are ongoing," he said.

Source: The Endocrine Society