GHRP2 Masks Human Growth Hormone use


by Anthony Roberts

Not too long ago, prior to the London Olympic Games of 2012, I threw down an article on something called GH2 (Growth Hormone Two), which is a form of Growth Hormone with a 20 kilodalton (20kda) weight, which is highly anabolic and (more importantly) could be used alone and remain undetected – or combined with regular growth hormone (rhGH) and mask its presence. Phone calls to the World Anti-Doping Agency weren’t returned.

The current growth hormone test administered to athletes relies on the ratio of two isoforms to detect cheating – the 20kda isoform (which nobody knew was available on the market until I wrote about it), and the 22kda version (which is the stuff we find in the ‘fridges of bodybuilders everywhere). Basically, when you inject the 22kda version of growth hormone, it suppresses the 20kda version, and the resulting ratio gets out of whack, and you fail the doping test. My solution was simply to inject the 20kda version and bring your ratios back into line. This is, of course, the same way we fool the testosterone:epitestosterone test (which still allows for a low dose of testosterone even without injecting some extra epitestosterone).

However, because growth hormone releasing peptides will elevate all of the isoforms, it stands to reason that one could simply inject a GHRP, such as GHRP-2, GHRP-6, or Hexarelin (my personal favorite), and fool the tests by bringing the GH isoforms back into something resembling the correct ratio. Admittedly, it’s not perfect, and I’m sure the ratio will remain somewhat skewed, but it’s enough to fool the doping controls.

A study published back in 2010 confirms the theory that a GHRP (in this case, GHRP-2) can mask growth hormone use in athletes attempting to avoid testing positive (1). The drawback? Scientists have developed a test for GHRP-2. But who cares? The detection window is less than five hours (2).

Here’s the study:

Influence of intravenous administration of growth hormone releasing peptide-2 (GHRP-2) on detection of growth hormone doping: growth hormone isoform profiles in Japanese male subjects.

Drug Test Anal. 2010 Nov-Dec;2(11-12):548-56.

Okano M, Nishitani Y, Sato M, Ikekita A, Kageyama S.

Abstract

Administration of exogenous 22 kDa recombinant human growth hormone (rhGH) suppresses the non-22 kDa pituitary growth hormone (GH) secretion by negative feedback; then, the elevated 22 kDa GH to non-22 kDa GH ratio (Rec/Pit ratio) can be utilized to detect doping with rhGH (isoform differential immunoassay). The influence of intravenous administration of growth hormone releasing peptide GHRP-2 on the isoform differential immunoassay for detecting rhGH doping has been investigated.In this study, a reference population (n=100) was used, with 0.04 mg/kg rhGH subcutaneous administration (n=5), 100 ?g of GHRP-2 intravenous administration (n=10) and 0.04 mg/kg rhGH combined with 100 ?g of GHRP-2 (n=10) in Japanese male subjects. The results indicated that the low dose (0.04 mg/kg) of rhGH led to significantly increased Rec/Pit ratio compared with the Japanese reference limit (P < 0.001). Because GHRP-2 dose led to increases in concentrations of both recombinant GH (recGH) and pituitary GH (pit GH), no significant change in the Rec/Pit ratio was observed (P > 0.05). In a combined administration study, after GHRP-2 dose the Rec/Pit ratios decreased to 39.9-43.9% compared with the elevated ratio caused by the rhGH dose.The results indicated that GHRP-2 administration cannot only be detected by the isoform differential immunoassay but also masks rhGH doping. The analysis of GHRP-2 was found to be suitable for compensating for the disadvantages of the isoform differential immunoassay because GHRP-2 and its metabolite (AA-3) in urine could be detected during the periods of masking of the Rec/Pit ratio by means of liquid chromatography/tandem mass spectrometry.
Copyright (c) 2010 John Wiley & Sons, Ltd.

References:
Drug Test Anal. 2010 Nov-Dec;2(11-12):548-56.
Influence of intravenous administration of growth hormone releasing peptide-2 (GHRP-2) on detection of growth hormone doping: growth hormone isoform profiles in Japanese male subjects.Okano M, Nishitani Y, Sato M, Ikekita A, Kageyama S.

Anal Bioanal Chem. 2012 Jan;402(3):1101-8. Epub 2011 Nov 15.
Growth hormone secretagogues: out of competition.
Pinyot A, Nikolovski Z, Bosch J, Such-Sanmartín G, Kageyama S, Segura J, Gutiérrez-Gallego R.Bioanalysis Group, Neurosciences Research Program, Municipal Institute for Medical Research-Hospital del Mar, 08003 Barcelona, Spain.
  
  

 

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