Molecular data
| Molecular formula | C1105H1770N318O336S26 (intact heterodimer, approximate) |
|---|---|
| Molecular weight | 36700 Da |
| Sequence | Human Chorionic Gonadotropin (hCG) — heterodimeric glycoprotein composed of a 92-residue α-subunit (shared with LH, FSH, TSH) and a 145-residue β-subunit unique to hCG |
| Sequence length | 237 residues |
| CAS / identifier | 9002-61-3 |
| Physical form | Lyophilized powder |
| Available sizes | 10,000 IU |
How it works
LH/hCG Receptor Activation
Human chorionic gonadotropin is a heterodimeric glycoprotein hormone that binds the shared LH/hCG receptor (LHCGR) with high affinity. Research shows hCG is roughly ten-fold more potent than luteinizing hormone at recruiting intracellular cAMP, making it a widely used tool for studying LHCGR pharmacology.
- High-affinity binding at the LHCGR plasma-membrane receptor
- ~10× more potent than LH in cAMP recruitment
- Studied as a model ligand for glycoprotein-hormone receptor signaling
Leydig Cell Testosterone Synthesis
In Leydig cell models, LHCGR activation raises cAMP, promoting StAR-mediated transfer of cholesterol into mitochondria. Cholesterol is then converted through the steroidogenic enzyme cascade (P450scc, 3β-HSD, CYP17, 17β-HSD) to testosterone.
- cAMP-driven StAR protein activation and cholesterol transport
- Engages the full P450scc → 17β-HSD steroidogenic pathway
- Used to study testosterone synthesis in primary Leydig cell cultures
Gonadal & Pregnancy Biology
Physiologically, hCG maintains the corpus luteum in early pregnancy and shares its receptor with LH. Research also examines downstream signaling differences between LH and hCG, including biased agonism and ER-stress responses in steroidogenic cells.
- Model compound for corpus luteum and early-pregnancy signaling
- Studied for biased agonism at the LH/CG receptor
- Used to investigate ER stress and steroidogenic enzyme regulation
What the research shows
Leydig Cell & Steroidogenesis
hCG is a standard stimulus for studying testosterone synthesis and the steroidogenic enzyme cascade in Leydig cell cultures.
Hormone Research 2001
LHCGR Signaling & Biased Agonism
Comparative studies of LH and hCG reveal distinct early-signaling profiles at the shared LH/CG receptor despite similar testosterone output.
Riccetti et al. 2016
ER Stress & Steroidogenic Regulation
Research examines how sustained hCG exposure can trigger endoplasmic-reticulum stress and modulate steroidogenic enzyme expression in testicular Leydig cells.
Park et al. 2014
Glycoprotein Hormone Pharmacology
hCG serves as a reference ligand for studying biased agonism and receptor signaling at the LH and LH/CG receptors.
Scientific Reports 2017
Specification
| Chemical Name | Human Chorionic Gonadotropin (hCG) |
|---|---|
| Structure | Heterodimeric glycoprotein (α + β subunits) |
| Amino Acids | 237 total (α-subunit 92, β-subunit 145) |
| Molecular Weight | ~36,700 Da |
| Potency | 10,000 IU per vial |
| Form | Lyophilized powder |
| Purity | ≥99% (HPLC verified) |
| Testing | Third-party HPLC, Mass Spec, Endotoxin |
| Storage (lyophilized) | -20°C for long-term stability |
| Storage (reconstituted) | 2–8°C, use promptly |
| Solubility | Bacteriostatic water for reconstitution |
| COA | Included with every order |
Frequently asked questions
What is HCG?
Human chorionic gonadotropin (hCG) is a heterodimeric glycoprotein hormone made of an alpha subunit (shared with LH, FSH and TSH) and a beta subunit unique to hCG. It acts on the LH/hCG receptor (LHCGR) and is widely used in endocrinology research as a stimulus for steroidogenesis and a model ligand for glycoprotein-hormone receptor signaling.
How does HCG work on Leydig cells?
hCG binds the LHCGR on Leydig cells, raising intracellular cAMP. cAMP promotes StAR-mediated transport of cholesterol into the mitochondria, where the steroidogenic enzyme cascade (P450scc, 3β-HSD, CYP17, 17β-HSD) converts it to testosterone. This makes hCG a standard tool for studying testosterone synthesis in vitro.
How is HCG different from luteinizing hormone (LH)?
hCG and LH act on the same receptor (LHCGR), but research shows they are not identical. hCG is roughly ten-fold more potent in cAMP recruitment and produces a distinct early-signaling profile, even though both ultimately drive similar testosterone synthesis in Leydig cell models. This phenomenon is studied as biased agonism.
Is HCG FDA approved?
hCG is an FDA-approved hormone in clinical pharmaceutical formulations. However, the research-grade hCG sold here is supplied strictly for in vitro laboratory research and is not the approved pharmaceutical product. It is not intended for human or veterinary therapeutic use.
What research contexts use HCG?
Research-grade hCG is used to study Leydig cell steroidogenesis, LHCGR receptor pharmacology and biased agonism, corpus luteum and reproductive biology, and endoplasmic-reticulum stress responses in steroidogenic cells.
How should research-grade HCG be stored?
Lyophilized hCG should be stored at -20°C, protected from light and moisture. Once reconstituted with bacteriostatic water, it should be kept refrigerated at 2–8°C and used promptly to preserve activity, as glycoprotein hormones lose potency over time in solution.
Literature
- PUBMED Effect of Human Chorionic Gonadotropin Derivatives on Leydig Cell Function
- PMC Human LH and hCG Stimulate Differently the Early Signalling Pathways but Result in Equal Testosterone Synthesis in Mouse Leydig Cells in Vitro
- PMC hCG-Induced Endoplasmic Reticulum Stress Triggers Apoptosis and Reduces Steroidogenic Enzyme Expression in Leydig Cells
- JOURNAL Human Luteinizing Hormone and Chorionic Gonadotropin Display Biased Agonism at the LH and LH/CG Receptors
For laboratory research use only. Not a drug, supplement, or medical product; not for human or animal use. All findings referenced are from published preclinical/laboratory research.