HCG 5,000iu (Human Chorionic Gonadotropin)

Human Chorionic Gonadotropin (HCG) is a glycoprotein hormone that plays a pivotal role in reproductive and endocrine research. It is primarily known for its function in pregnancy, where it supports the corpus luteum and stimulates the production of progesterone, essential for maintaining the uterine lining. HCG is also utilized in various research contexts to study its effects on reproductive tissues and its potential in modulating endocrine pathways.

The 5,000 IU preparation of HCG is manufactured to meet high purity standards, ensuring reliable results in in vitro research applications. This preparation is specifically designed for research purposes and is not intended for human consumption. Volta Peptides provides HCG for research use, allowing scientists to explore its biological functions and potential applications in reproductive biology.

Human chorionic gonadotropin is not a peptide in the sense that the rest of this catalogue uses the word. It is a heterodimeric glycoprotein hormone of roughly 36.7 kilodaltons, built from two non-covalently associated subunits, and about a third of its mass is carbohydrate rather than protein. That composition is not incidental packaging: the sugar chains determine how long the hormone survives in circulation and how it behaves at its receptor.

The alpha subunit is 92 amino acids and is shared identically with luteinising hormone, follicle-stimulating hormone and thyroid-stimulating hormone. All the specificity lives in the beta subunit, 145 amino acids, whose C-terminal extension is what distinguishes hCG from luteinising hormone. That extension carries additional O-linked glycosylation and is the main reason hCG persists far longer in circulation than LH does.

Both hormones act at the same receptor, the luteinising hormone and choriogonadotropin receptor, LHCGR. It is a class A G protein-coupled receptor signalling principally through Gs and cyclic AMP, and in the gonads that drives steroidogenesis: testosterone production by testicular Leydig cells, and in the ovary the events of follicular maturation and luteinisation. Because hCG and LH share the receptor but differ in duration, hCG behaves as a long-acting LH surrogate rather than as a distinct signal.

Research has extensively documented the role of HCG in reproductive biology, particularly in its capacity to support the corpus luteum during early pregnancy. HCG is secreted by the syncytiotrophoblast cells of the placenta and is crucial for the maintenance of progesterone production by the corpus luteum, which is necessary for a successful pregnancy (Cole, L.A., 'Biological functions of hCG and hCG-related molecules', Reproductive Biology and Endocrinology, vol. 8, 2010).

In addition to its role in pregnancy, HCG is also studied for its effects on male fertility. Studies in animal models have demonstrated that HCG can stimulate the production of testosterone by the Leydig cells in the testes, thereby influencing spermatogenesis (Veldhuis, J.D., 'Regulation of pulsatile testosterone secretion: physiological and clinical implications', Endocrine Reviews, vol. 11, no. 1, 1990).

HCG is a valuable tool in endocrine research due to its ability to interact with the luteinizing hormone/chorionic gonadotropin receptor (LHCGR). This interaction is crucial for stimulating steroidogenesis in gonadal tissues, making it a subject of interest for studies on hormonal regulation and endocrine disorders (Ascoli, M., 'The gonadotropin receptors', Endocrine Reviews, vol. 23, no. 2, 2002).

Research has also explored the potential of HCG in modulating the immune response during pregnancy. Studies suggest that HCG may play a role in immune tolerance, which is essential for preventing the maternal immune system from rejecting the fetal allograft (Arck, P.C., 'Stress and immune mediators in miscarriage', Human Reproduction Update, vol. 7, no. 4, 2001).

HCG has been studied in the context of cancer research, particularly for its role in trophoblastic diseases and certain types of testicular cancer. Elevated levels of HCG are often used as a biomarker for these conditions, aiding in diagnosis and monitoring of treatment efficacy (Stenman, U.H., 'Tumor markers in clinical practice: a review focusing on common solid cancers', Medical Principles and Practice, vol. 12, 2003).

Research has also investigated the potential of HCG in influencing tumor growth and progression. Some studies suggest that HCG may have an inhibitory effect on certain cancer cell lines, although the mechanisms remain to be fully elucidated (Cole, L.A., 'hCG, the wonder of today's science', Reproductive Biology and Endocrinology, vol. 8, 2010).

Beyond its reproductive functions, HCG has been explored in metabolic research. Studies have investigated its influence on fat metabolism, particularly in the context of weight regulation and obesity research. However, findings are mixed, and further research is needed to clarify its role and efficacy in metabolic pathways (Greenway, F.L., 'Physiological adaptations to weight loss and factors favouring weight regain', International Journal of Obesity, vol. 39, 2015).

Animal studies have also examined the effects of HCG on energy expenditure and appetite regulation, providing insights into its potential mechanisms of action in metabolic processes (Roth, J., 'The Obesity Epidemic: A Challenge for the Future', Frontiers in Endocrinology, vol. 1, 2010).

Every other vial in this catalogue is sold by mass, because a synthetic peptide is one molecule and a milligram of it is a defined quantity. hCG is sold in International Units, and the difference is not a labelling convention. It reflects what the material actually is.

hCG is a glycoprotein, and its carbohydrate chains vary. Preparations from different sources contain mixtures of glycoforms: identical amino acid sequence, different sugar structures, and different biological activity per unit mass. A milligram of one preparation and a milligram of another are not equivalent, so mass is the wrong unit for potency.

An International Unit is defined by biological activity measured against a reference standard, which is the only unit that means the same thing across preparations. That is why a certificate for this product should report a bioassay or an activity determination, not only a purity percentage, and why a certificate quoting only milligrams is describing the wrong property.

For a synthetic peptide, high performance liquid chromatography purity answers a clean question: what proportion of the material is the single intended molecule. For a glycoprotein, the intended material is itself a distribution of glycoforms, so a single sharp peak is not necessarily the goal and a broadened one is not necessarily a defect.

The realistic impurities are also different in kind. Free alpha and free beta subunits can be present alongside the assembled heterodimer, and the alpha subunit is identical to that of three other hormones. Since the subunits are held together non-covalently rather than by a disulfide bridge between them, dissociation is a genuine failure mode rather than a theoretical one.

Reviews of glycoprotein hormone subunits describe free subunits as having actions of their own, distinct from those of the intact dimer. A preparation containing appreciable free subunit is therefore not simply a diluted one.

hCG and luteinising hormone bind the same receptor. What separates them is duration: the beta subunit C-terminal extension and its glycosylation give hCG a substantially longer circulating half-life, so it produces a sustained signal where the endogenous hormone is pulsatile.

That property is exactly why it is used to substitute for the endogenous luteinising hormone surge in assisted reproduction, and why hCG stimulation testing works as a diagnostic probe of Leydig cell function: a single administration produces a measurable, prolonged steroidogenic response.

It also means the pharmacology cannot be inferred from LH physiology alone. A sustained agonist at a receptor normally exposed to pulses is a different intervention from more of the natural signal, which is the same distinction that separates the DAC and no-DAC GHRH analogues elsewhere in this catalogue.

hCG is a genuine medicine with approved indications in reproductive endocrinology, unlike most compounds in this catalogue. It is also a large, non-covalently assembled glycoprotein and is correspondingly more fragile than a short synthetic peptide: dissociation of the subunits and loss of activity are realistic outcomes of poor handling, and neither necessarily shows up as a change in mass.

Because potency is a biological property rather than a mass, degradation can occur without the material looking different by simple analysis. Activity determination is what detects it.

Material supplied for research is for in-vitro laboratory use only. Nothing summarised here is guidance for use in humans or animals, and its approved clinical uses are not the context in which research material is supplied.