Introduction:

Synthetic Growth hormone, also known as rhGH, is a remarkable discovery in the realm of human physiology. This 22kDa isomer of the naturally occurring growth hormone has garnered significant attention in scientific literature. It's often referred to as "Growth Hormone 1" in recognition of its uniqueness among various growth hormone isomers. Each isomer is a distinct chemical entity, sharing the same atomic composition but possessing distinct properties. In this article, we delve into the lesser-known 20kDa Growth Hormone variant, GH2, and explore its intriguing characteristics.

The Enigma of GH2:

GH2, or Growth Hormone Two, represents the 20kDa isomer of Growth Hormone, a naturally occurring variant that makes up a small fraction of the pituitary and serum GH. Derived from the same gene but through alternative mRNA splicing, GH2 differs from its more common counterpart, GH1 (22kDa), primarily in its amino acid region (E32-Q46). Notably, GH2 has shown a higher absorption rate in certain cells compared to regular GH.

Unmasking Growth Hormone Doping:

The World Anti-Doping Agency employs a test that relies on the ratio of 20:22kDa to detect growth hormone use. Standard rhGH elevates the levels of the 22kDa isomer while lowering the 20kDa level, indicating growth hormone use. However, GH2 can disrupt this ratio, serving as an effective masking agent against the current WADA test.

Enhanced Potency:

GH2's unique properties extend to its reduced susceptibility to binding by hGH-Binding Proteins. Consequently, GH2 can exert a more robust effect than regular hGH on tissues releasing hGH-BP. This characteristic suggests its potential potency in areas like fat loss. Additionally, GH2 exhibits a longer clearance time, likely due to its lower affinity to binding proteins or a diminished impact on the GH-axis negative feedback loop.

The Role of IGF-1:

While growth hormone directly interacts with specific cell surface receptors, most of its anabolic effects stem from the generation of Insulin-like Growth Factor 1 (IGF-1). IGF-1 is renowned for its profound metabolic effects across various cell types. Interestingly, GH2 has demonstrated an ability to stimulate the production of IGF-1 similar to, if not greater than, GH1.

Fat-Burning Potential:

The lipolytic (fat-burning) effects of growth hormone are closely linked to increased IGF-1 levels rather than GH elevation itself. GH2's capacity to enhance IGF-1 production implies it may have comparable fat-burning potential.

Scientific Insights:

A study published in The Journal of Clinical Endocrinology & Metabolism explored GH2's impact on normal men. It showed that GH2 raised 20kDa-hGH levels in a dose-dependent manner while suppressing 22kDa-hGH secretion. This underscores GH2's potential to stimulate growth-promoting and lipolytic activities. Additionally, GH2 significantly elevated IGF-1 levels, indicating its ability to exert GH actions.

Human Studies:

Further research highlights GH2's anabolic potential. Lower concentrations of 20kDa-hGH have shown stronger induction of muscular IGF-I (mIGF-1) gene expression compared to the 22kDa-hGH isomer, at least in mice. Moreover, GH2's effect on elevating IGF-1 levels suggests it could be more anabolic than regular rhGH, or equally effective at a lower dose. Human studies also support GH2's utility for Growth Hormone replacement therapy in GH-deficient adults.

Conclusion:

In conclusion, GH2 emerges as an intriguing variant in the world of growth hormones. Its unique properties, including a longer active life, enhanced impact on IGF-1 levels, and potential anabolic effects, make it a subject of considerable interest. While further research is needed to fully understand its mechanisms and applications, GH2 presents an exciting avenue for exploration in the field of human physiology. And the best part? It's cost-effective, making it an accessible option for those seeking to harness its potential.