Agonists and antagonists at receptors for relaxin and relaxin-related peptides LDLa is the unique N-terminal region found in type C-glycoprotein receptors; the RXFP1-truncate is a naturally occurring splice variant of the receptor that includes the LDLa region and acts as a functional antagonist at the RXFP1 receptor (Scott et al., 2005c).
Receptor | Previous Name | Agonist | Antagonist | Radioligand |
|---|---|---|---|---|
| RXFP1 | LGR7 | H2 relaxin > H1 relaxin > H3 relaxin ≫ INSL3 | RXFP1-truncate | 33P-H2 relaxin, 125I-H2 relaxin |
| RXFP2 | LGR8 | INSL3 > H2 relaxin = H1 relaxin ≫ H3 relaxin | INSL3 B chain analoga; (des 1–8) A chain INSL3 analogb | 33P-H2 relaxin, 125I-H2 relaxin, 125I-INSL3 |
| RXFP3 | GPCR135, SALPR | H3 relaxin > H3 relaxin B chain | INSL5 | 125I-H3 relaxin, 125I-H3-B/INSL5 A chimera |
| RXFP4 | GPCR142, GPR100 | INSL5 = H3 relaxin > H3 relaxin B chain |
| 125I-H3 relaxin, 125I-H3-B/INSL5 A chimera |