Description

SPECIFICATION	DETAILS
Product Name	Human Chorionic Gonadotropin (HCG)
Synonyms	hCG, Chorionic Gonadotropin, Choriogonin
CAS Number	9002-61-3
Type	Glycoprotein Hormone (heterodimeric)
Chemical Formula	C₁₁₀₅H₁₇₇₀N₃₀₆O₃₃₆S₂₆
Molecular Weight	~36.7 kDa (glycoprotein; ~14.5 kDa α-subunit + ~22.2 kDa β-subunit)
Subunit Composition	α-subunit: 92 amino acids (shared with LH, FSH, TSH)β-subunit: 145 amino acids (unique, confers specificity)
Total Amino Acids	237 residues (heterodimeric)
Carbohydrate Content	~31% by weight (N-linked and O-linked glycosylation)
Isoelectric Point (pI)	~2.95
Potency	5000 IU per vial
Form	Lyophilized (freeze-dried) powder
Purity / Concentration	≥99%
Appearance	White to off-white lyophilized cake or powder
Vial Type	3mL sealed glass vial with flip-top cap
Third-Party Tested	Yes — Certificate of Analysis (COA) available
Application	Research use of gonadotropins in reproductive, endocrine, and metabolic pathways
Storage	≤25°C sealed; after opening, refrigerate 2–8°C; long-term: −20°C
Shelf Life	24 months when stored properly (lyophilized)
Reconstitution	Reconstitute with bacteriostatic water or sterile solvent (sold separately)

Human Chorionic Gonadotropin (HCG) Research Reagent — 5000 IU

Peptide Minds offers a high-purity Human Chorionic Gonadotropin (HCG) research reagent, supplied as a lyophilized powder in a sealed 3mL glass vial containing 5000 IU of active compound. This product is manufactured exclusively for controlled in vitro research and laboratory applications and is not intended for human consumption, clinical use, or veterinary purposes.

Molecular Profile

HCG is a heterodimeric glycoprotein hormone composed of 237 amino acid residues organized into two non-covalently associated subunits. The α-subunit consists of 92 amino acids and is structurally identical to the α-chains of luteinizing hormone (LH), follicle-stimulating hormone (FSH), and thyroid-stimulating hormone (TSH). The β-subunit contains 145 amino acids, including a unique carboxy-terminal peptide (CTP) extension containing four glycosylated serine residues that distinguishes it from the LH β-subunit. The total molecular weight of the intact glycoprotein is approximately 36.7 kDa, with carbohydrate moieties constituting roughly 31% of the total mass. The molecule features both N-linked and O-linked glycosylation sites that contribute to its characteristic low isoelectric point (~2.95) and extended stability profile in biological systems.

Laboratory Research Applications

In laboratory settings, HCG has been utilized as a research reagent in multiple experimental contexts. Published studies have employed this glycoprotein in cell-based assays examining LH/CG receptor (LHCGR) activation, cyclic adenosine monophosphate (cAMP) signaling pathway characterization, and downstream extracellular signal-regulated kinase (ERK1/2) phosphorylation events. In vitro studies using HEK293 cells, murine Leydig cell preparations, and human granulosa cell cultures documented HCG-mediated receptor engagement as measured by bioluminescence resonance energy transfer (BRET) and Western blot analysis. Animal model investigations examined HCG as a probe for gonadal receptor activity, steroidogenic pathway mapping, and reproductive-axis signaling in controlled experimental designs. Researchers have also utilized HCG as a biological reference standard in immunoassay development and gonadotropin quantification protocols.

Intended Use

This product is sold strictly for in vitro laboratory research and educational purposes. It is NOT intended for human or veterinary use. No applications as a drug, food additive, household chemical, or cosmetic are authorized or implied. The purchaser assumes full responsibility for compliance with all applicable regulations governing the use of research compounds in their jurisdiction.

Quality Assurance & Testing

Each batch of HCG from Peptide Minds undergoes rigorous quality control. Potency is confirmed through bioassay and immunoassay methods consistent with USP reference standards. A Certificate of Analysis (COA) documenting batch-specific analytical data, including potency, purity, and identity confirmation, is provided with every order.

Handling and Storage

Store lyophilized HCG at ≤25°C in its original sealed container, protected from light, heat, and moisture. Under these conditions, the compound maintains stability for up to 24 months. After reconstitution with an appropriate sterile solvent (e.g., bacteriostatic water), the solution should be refrigerated at 2–8°C and used within 30 days. For extended storage of reconstituted material, aliquot and store at −20°C. Avoid repeated freeze-thaw cycles to maintain structural integrity. Addition of a carrier protein (0.1% BSA) is recommended for dilute reconstituted preparations to prevent adsorptive losses.

 Research Background

Discovery & Historical Context

Human Chorionic Gonadotropin occupies a central position in the history of reproductive endocrinology research. The identification of a gonadotropic factor in pregnancy-associated biological specimens dates to the early twentieth century. Aschheim and Zondek first demonstrated in 1927 that urine from pregnant individuals contained a substance capable of inducing ovarian changes when administered to immature mice, establishing one of the earliest biological pregnancy detection methods.

Subsequent biochemical characterization over the following decades established HCG as a glycoprotein hormone produced by trophoblast cells. The heterodimeric structure was elucidated through protein chemistry approaches, revealing the shared α-subunit architecture common to the pituitary glycoprotein hormone family (LH, FSH, TSH) and the unique β-subunit that confers biological specificity to HCG. The complete amino acid sequences of both subunits were determined by the 1970s, and recombinant forms became available through genetic engineering approaches in later decades.

The development of monoclonal antibody technology in the 1980s enabled highly specific immunoassays targeting the β-subunit of HCG, which became the foundation for modern quantitative detection methods used in research laboratories globally. The glycoprotein has since been identified in multiple molecular variants, including intact HCG, hyperglycosylated HCG, free β-subunit, nicked HCG, and various degradation fragments — each with distinct biochemical properties and detection characteristics.

Structural Characteristics

HCG belongs to the cystine knot growth factor superfamily of glycoproteins. The molecule exists as a non-covalently associated heterodimer consisting of an α-subunit (92 amino acids, ~14.5 kDa including carbohydrate) and a β-subunit (145 amino acids, ~22.2 kDa including carbohydrate). The gene encoding the α-subunit (CGA) is mapped to human chromosome 6q14.3. The β-subunit genes (CGB cluster) are located on chromosome 19q13.33.

The α-subunit shares greater than 85% sequence identity with the α-chains of LH, FSH, and TSH. The β-subunit is structurally related to LHβ but contains an extended carboxy-terminal peptide (CTP) of approximately 30 additional amino acids bearing four O-linked glycosylation sites on serine residues. This CTP extension is responsible for the longer circulating half-life observed for HCG compared to LH in pharmacokinetic studies. The extensive glycosylation (~31% carbohydrate by weight) includes both N-linked oligosaccharide chains and O-linked sugar moieties that influence receptor binding affinity, biological activity, and stability.

Nuclear magnetic resonance and X-ray crystallographic studies have characterized the three-dimensional structure, revealing the characteristic cystine knot motif formed by three disulfide bonds in each subunit. The α-subunit contains five disulfide bonds, while the β-subunit contains six. These structural features contribute to the molecule’s thermal stability and resistance to proteolytic degradation.

Receptor Systems Investigated in Research

Laboratory investigations have characterized HCG interactions with the luteinizing hormone/chorionic gonadotropin receptor (LHCGR), a G protein-coupled receptor expressed in gonadal tissues. Cell-based studies demonstrated that HCG binding to LHCGR activated the classical cAMP/protein kinase A (PKA) signaling cascade, as measured by BRET-based cAMP biosensor assays in transfected HEK293 cell systems.

Comparative receptor pharmacology studies revealed that HCG and LH, despite binding the same receptor, exhibited biased agonism with distinct signaling profiles. Research conducted using both recombinant and extractive preparations demonstrated that HCG was approximately 10-fold more potent than LH in cAMP recruitment, with differential effects on ERK1/2 phosphorylation and β-arrestin 2 activation pathways. These findings were documented through dose-response experiments employing BRET and FRET technologies in living cells.

Studies using human primary granulosa cell cultures and mouse Leydig tumor cell lines (mLTC-1) further characterized LHCGR-mediated intracellular signaling differences between LH and HCG. In human granulosa cells, LH preferentially activated ERK1/2- and AKT-dependent proliferative signals, while HCG predominantly activated progestational cAMP/PKA pathways. Mutational analysis of LHCGR identified specific leucine-rich repeat (LRR) domain residues involved in discriminating LH versus HCG-specific binding and signal transduction.

Laboratory Methodologies

Research protocols employing HCG have utilized a range of standardized laboratory methodologies, including:

• Cell Culture Assays: In vitro studies using HEK293 cells, murine primary Leydig cells, mouse Leydig tumor cells (mLTC-1), human granulosa-lutein cells (hGLC), and trophoblast cell lines to assess LHCGR-mediated cAMP accumulation, ERK1/2 phosphorylation, AKT activation, and steroidogenic gene expression.
• Receptor Pharmacology: BRET and FRET-based biosensor assays for real-time, quantitative measurement of cAMP kinetics, β-arrestin 2 recruitment, and G protein coupling in living cell systems expressing wild-type or mutant LHCGR constructs.
• Animal Model Studies: In vivo gonadotropin bioassays in rodent models measuring ovarian weight gain, ovulation induction, and testicular steroidogenic endpoints. HCG has been administered via intravenous, intraperitoneal, and subcutaneous routes in dose-response experimental designs.
• Immunoassay Development: HCG serves as a reference standard in sandwich immunoassay systems employing monoclonal antibodies specific to the β-subunit. Chromatographic, lateral flow, and ELISA-based detection platforms have been developed using HCG as the target analyte.
• Steroidogenesis Profiling: Western blot analysis of StAR protein (Steroidogenic Acute Regulatory protein) expression, CREB phosphorylation, and downstream testosterone/progesterone quantification by radioimmunoassay (RIA) or liquid chromatography-mass spectrometry (LC-MS) in HCG-treated cell preparations.
• Structural Analysis: Characterization by SDS-PAGE, size-exclusion chromatography, mass spectrometry, and glycan profiling to confirm heterodimeric integrity, molecular weight, and glycosylation patterns.

Analytical Characterization

Identity and potency verification in research settings typically employs multiple orthogonal analytical approaches. Bioassay methods based on the USP reference standard protocol measure gonadotropic activity in International Units (IU). SDS-PAGE under reducing and non-reducing conditions confirms subunit integrity and apparent molecular weight. Immunoassay-based methods using β-subunit-specific monoclonal antibodies provide quantitative potency assessment. Size-exclusion HPLC and ion-exchange chromatography assess heterodimer integrity and charge variant distribution. Mass spectrometric analysis confirms molecular identity and glycosylation profile.

The glycosylation state is a critical quality attribute, as variations in N-linked and O-linked glycan structures influence receptor binding kinetics, biological potency, and circulatory clearance rates in experimental systems. Analytical protocols should assess glycosylation patterns, as this feature distinguishes different HCG preparations and may affect reproducibility of downstream experimental results.

Peer-Reviewed References

1. Casarini L, et al. LH and hCG action on the same receptor results in quantitatively and qualitatively different intracellular signalling. PLoS One. 2012;7(10):e46682.
2. Casarini L, et al. Two Hormones for One Receptor: Evolution, Biochemistry, Actions, and Pathophysiology of LH and hCG. Endocrine Reviews. 2018;39(5):549–592.
3. Riccetti L, et al. Human LH and hCG stimulate differently the early signalling pathways but result in equal testosterone synthesis in mouse Leydig cells in vitro. Reproductive Biology and Endocrinology. 2017;15:2.
4. Casarini L, et al. Identification of Key Receptor Residues Discriminating Human Chorionic Gonadotropin (hCG)- and Luteinizing Hormone (LH)-Specific Signaling. International Journal of Molecular Sciences. 2021;22(1):151.
5. Fournier T, et al. Human Luteinizing Hormone and Chorionic Gonadotropin Display Biased Agonism at the LH and LH/CG Receptors. Scientific Reports. 2017;7:940.
6. Cole LA. Biological functions of hCG and hCG-related molecules. Reproductive Biology and Endocrinology. 2010;8:102.

 Regulatory & Compliance Statement

FOR RESEARCH USE ONLY NOT FOR HUMAN CONSUMPTION OR VETERINARY USE This product is sold exclusively for in vitro laboratory research and educational applications. It is not approved by the U.S. Food and Drug Administration (FDA) for human use, clinical applications, or therapeutic purposes. Peptide Minds (Accelairate LLC) is a chemical supplier. Peptide Minds is not a compounding pharmacy or chemical compounding facility as defined under Section 503A of the Federal Food, Drug, and Cosmetic Act, and is not an outsourcing facility as defined under Section 503B of the same Act. By purchasing from Peptide Minds, the buyer agrees that all products will be used in accordance with applicable laws and regulations, and assumes full responsibility for their use in appropriate research settings only. All technical and descriptive information on this website is provided for research, educational, and informational purposes only. The products and any statements made about them have not been evaluated by the U.S. Food and Drug Administration. The products are not intended to diagnose, treat, cure, or prevent any disease or medical condition.

 

Disclosure

The listing of frequently researched-together compounds on this product page is based on published research literature and is provided for informational context only. Peptide Minds does not endorse or recommend the concurrent use of research compounds. All products are sold independently for standalone laboratory research applications and are intended for in vitro research and educational purposes only.