Table 2.
Differences between LH and hCG
| LH | hCG | |
|---|---|---|
| Secreted by | Pituitary | Embryo and placenta |
| Physiological role | Support follicle development (14 days) | Support implantation and pregnancy (282 days) |
| Binding affinity | Lower | Higher (2x) |
| Half-life | Shorter (23 h sc) | Longer (32–33 h sc) |
| Accumulation | Slight | Significant and down regulation of LH receptor |
| Stimulation of LH receptor | Physiological | Pharmacological, leading to LH receptor down regulation |
| Equivalency | 6–8 IU of LH | 1 IU of hCG |
| Purity | 99% | 99% purity for r-hCG and 70% in HP-hMG (39 identified contaminants) |
| Sources | r-hLH | r-hCG, urinary hCG or hMG |
| Induction of steroid (testosterone, oestradiol and progesterone) production | Higher LH = higher steroid production | Higher hCG = higher steroid production |
| Filling system | Filled by mass | Filled by Mass for r-hCG and Filled by IU for hCG/hMG |
| Gene activation | Differential unexplained | Differential unexplained |
| Cytokine production | Differential unexplained | Differential unexplained |
| Embryo quality production | Not objectively proven | Not objectively proven |
h hours; hCG human chorionic gonadotropin; IU international units; LH luteinising hormone; sc subcutaneous.