Oxytropin

Product status information

Chemical reagent intended exclusively for laboratory tests (Research Use Only). It is not a medicinal product, dietary supplement or food. It is not intended for use on humans or animals. Sales only to registered research units and laboratories.

REGULATORY STATUS

Somatropin (recombinant human growth hormone) has equivalents registered as drugs – among others Genotropin®, Omnitrope®, Norditropin®, Humatrope®, Saizen® — used for strictly defined endocrine indications. Oxytropin as a research reagent is not a substitute for any of these medicines, is not intended for the treatment of growth hormone deficiency or any other clinical applications and does not replace medical consultation.

Growth hormone, its fragments and releasing agents are on the WADA Prohibited List in section S2 (peptide hormones, growth factors, related substances and mimetics) — substance prohibited at all times. Athletes registered in the ADAMS system verify the current list before making any decision. Marketing the product as “HGH for mass”, “growth hormone for regeneration”, “anti-aging” or “rejuvenation injection” is contrary to the Research Use Only framework.

Oxytropin is the trade name under which Pro-Body (Endogenic line) supplies somatropin – recombinant human growth hormone (rhGH) — as a research reagent. The “100 IU without water” variant specifies two things: a total content of 100 international units of somatropin (corresponding to approximately 33.3 mg of the substance) and the form of lyophilisate supplied without solvent.

The latter is the essence of the offer here – unlike variant with bacteriostatic water, the kit does not contain bacteriostatic water, so the reconstitution solvent is selected and delivered by the researcher separately. This gives you full control over the volume of the solvent and the concentration of the working solution, and the lyophilisate remains in the most stable, dry form until preparation.

Somatropin is the protein at the upstream end of the GH/IGF-1 somatotropin axis: growth hormone secreted by the pituitary gland stimulates the liver and peripheral tissues to produce insulin-like growth factor (IGF-1), and the entire system controls the metabolism of proteins, fats and carbohydrates. Oxytropin supplies growth hormone itself – unlike secretagogues, which stimulate the secretion of endogenous GH, and IGF-1 analogues, which represent a peripheral effector of this axis.

We discuss this distinction below because it can be a source of confusion. The identity, purity and activity of each batch is confirmed by a certificate of analysis (COA).

Human growth hormone (hGH, somatotropin) is a single-chain protein composed of 191 amino acid residues with a molecular weight of 22 kDa, secreted in pulses by somatotropic cells of the anterior pituitary. Somatropin is its recombinant equivalent – a molecule with a sequence identical to the sequence of pituitary hormone, obtained by recombinant DNA technology (typically in a bacterial or mammalian expression system).

In the reagent trade, it serves as a reference material for research on the physiology and pharmacology of the GH/IGF-1 axis. Growth hormone works in two ways. Some of its effects are caused directly by binding the growth hormone receptor (GHR) on target cells – these include lipolytic activity in adipose tissue and influence on carbohydrate metabolism.

However, a significant part of the effects is indirect and proceeds through IGF-1, the production of which is induced by GH in the liver – this is the pathway responsible for, among other things, the anabolic effect on proteins and tissues. This duality (direct action of GH and indirect action through IGF-1) is the foundation on which research on this axis is based.

Chemically, Oxytropin is recombinant somatropin, a 191-amino acid protein delivered as a lyophilized product for reconstitution by the researcher.

• Trade name: Oxytropin (Pro-Body, Endogenic line)
• Substance: somatropin — recombinant human growth hormone (rhGH)
• Sequence: single-chain protein of 191 amino acid residues, identical to pituitary hGH; two disulfide bridges
• Molecular weight: approx. 22 kDa (22.1 kDa) – approximate value, the batch-specific mass determined by MS is authoritative
• CAS number: 12629-01-5 (somatropin) – to be confirmed in the batch COA
• Contents: 100 IU total (≈ 33.3 mg somatropin at the conversion rate of 3 IU/mg); configuration of vials according to batch specifications
• Delivered form: freeze-dried without water — no solvent included; reconstitution is performed by the researcher using their own solvent
• Origin: DNA recombination; purity and identity according to the batch COA

Characteristics table

Somatropin binds growth hormone receptor (GHR) — a receptor from the cytokine receptor family. A single hormone molecule binds two receptor molecules, leading to its functional dimerization and activation of the kinase JAK2 bound to the receptor. This triggers a signaling cascade in which a central role is played by the transcription factors STAT5 — after phosphorylation, they move to the nucleus and regulate the transcription of target genes, including the IGF-1 gene. The profile described in the literature includes:

1. IGF-1 induction — activation of GHR/JAK2/STAT5 in the liver increases the production of insulin-like growth factor 1, the main mediator of the anabolic and growth effects of the axis
2. Lipolytic action — direct effect of GH on adipocytes, described as mobilization of fatty acids and modulation of fat metabolism
3. Effect on protein metabolism — indirectly, through IGF-1, in the context of protein synthesis and nitrogen balance in models
4. Impact on carbohydrate metabolism — GH has an antagonistic effect on insulin (counterregulatory), which makes carbohydrate metabolism an important element of the full characterization of the hormone
5. Water and electrolyte management — sodium and water retention were reported in the growth hormone profile

Oxytropin is used as a reagent in work on the somatotropin axis. The working concentrations and route of administration in the model are selected by the researcher – the product does not define either doses or schedules. Main research directions:

• Regulation of the GH/IGF-1 axis — somatropin as a reference material in studies of feedback and IGF-1 production
• GHR receptor signaling — receptor dimerization, JAK2/STAT5 pathway and transcription regulation in cell models
• Protein, lipid and carbohydrate metabolism — studies of direct and indirect (IGF-1-dependent) effects of the hormone in cellular systems
• Comparisons of forms and variants of rhGH — assessment of stability, identity and activity of various forms and batches of somatropin
• Analytical and anti-doping methods — somatropin as a reference analyte in the development of methods for identifying and determining growth hormone

The term “without water” means that the kit does not include any solvent — the researcher selects it and delivers it separately. This distinguishes this variant from the “water” form, in which the solvent is included. Practical consequences:

• Solvent: typical bacteriostatic water (sterile water with the addition of a bacteriostatic agent) — selected and supplied by the researcher; the volume determines the concentration of the working solution
• Concentration control: because the volume of the solvent is determined by the researcher, the concentration of the working solution is fully under their control – the product does not impose doses or concentrations
• Protein reconstitution: the solvent is not introduced directly onto the lyophilisate cake, but in a slow stream along the wall of the vial; vials should not be shaken — just swirl it gently until it dissolves, because shaking foams the solution and denatures the protein
• Visual inspection: after reconstitution, the solution should be clear; a solution that is cloudy, discolored or contains sediment should not be used for work

• Lyophilisate (unopened vial): −20 °C for long-term storage; permissible 2-8 °C in the shorter term; protect from light and moisture, in the original, unopened vial
• Reconstituted solution: refrigerator 2–8 °C, protected from light; protein in the aqueous phase is less stable than lyophilisate – prepare portions corresponding to the current needs of the protocol
• Freezing the solution: the finished solution is not routinely frozen because freeze-thaw cycles destabilize the protein; if the protocol requires longer storage, the solution is divided into aliquots and avoids repeated freezing and thawing of the same aliquot
• Keep out of the reach of unauthorized persons – laboratory material, not intended for consumer sale

Oxytropin 100 IU is somatropin – recombinant human growth hormone (rhGH), a 191-amino acid protein with a mass of approximately 22 kDa, identical to the pituitary hormone – supplied as a research reagent of the Endogenic line in the form of freeze-dried without water (no solvent included; reconstitution by investigator). The content of 100 IU corresponds to approximately 33.3 mg of the substance.

Somatropin is the upstream component of the GH/IGF-1 axis: it binds the growth hormone receptor (GHR), activates the JAK2/STAT5 pathway and induces the production of IGF-1, combining the direct effects of the hormone (lipolysis, carbohydrate metabolism) with indirect effects through IGF-1 (protein metabolism). The “water-free” variant transfers control over the solvent and working concentration to the researcher, and the lyophilisate remains in its most stable form until preparation.

Somatropin should be distinguished from secretagogues that stimulate endogenous GH and from IGF-1 analogues (peripheral effector). Purity and identity according to batch COA (HPLC/SDS-PAGE, MS/peptide mapping, activity assay). Regulatory Status – Research Use Only; somatropin has medicinal equivalents (Genotropin® and related) which the reagent does not replace; WADA S2 (prohibited at all times).

1. Ranke MB, Wit JM (2018). Growth hormone – past, present and future. PubMed
2. Dehkhoda F, Lee CMM, Medina J, Brooks AJ (2018). The Growth Hormone Receptor: Mechanism of Receptor Activation, Cell Signaling, and Physiological Aspects. PubMed
3. World Anti-Doping Agency. Prohibited List (S2: Peptide Hormones, Growth Factors, Related Substances and Mimetics – Growth Hormone). WADA: Prohibited List