Table 2.
Molecular structure of gonadotropin-inhibitory hormone (GnIH) peptides in chordates.
| Chordates | Peptide name | Molecular structure |
|---|---|---|
| Mammals | Human RFRP-1 | MPHSFANLPLRFa |
| Human RFRP-3 | VPNLPQRFa | |
| Macaque RFRP-3 | SGRNMEVSLVRQVLNLPQRFa | |
| Bovine RFRP-1 | SLTFEEVKDWAPKIKMNKPVVNKMPPSAANLPLRFa | |
| Bovine RFRP-3 | AMAHLPLRLGKNREDSLSRWVPNLPQRFa | |
| Rat RFRP-3 | ANMEAGTMSHFPSLPQRFa | |
| Siberian hamster RFRP-1 | SPAPANKVPHSAANLPLRFa | |
| Siberian hamster RFRP-3 | TLSRVPSLPQRFa | |
| Birds | Quail GnIH | SIKPSAYLPLRFa |
| Quail GnIH-RP-2 | SSIQSLLNLPQRFa | |
| Chicken GnIH | SIRPSAYLPLRFa | |
| European starling GnIH | SIKPFANLPLRFa | |
| Zebra finch GnIH | SIKPFSNLPLRFa | |
| Reptiles | Red-eared slider GnIH | SIKPVANLPLRFa |
| Red-eared slider GnIH-RP-1 | STPTVNKMPNSLANLPLRFa | |
| Red-eared slider GnIH-RP-2 | SSIQSLANLPQRFa | |
| Amphibians | Bullfrog GRP/R-RFa | SLKPAANLPLRFa |
| Bullfrog GRP-RP-1 | SIPNLPQRFa | |
| Bullfrog GRP-RP-2 | YLSGKTKVQSMANLPQRFa | |
| Bullfrog GRP-RP-3 | AQYTNHFVHSLDTLPLRFa | |
| Red-bellied newt LPXRFa-1 | SVPNLPQRFa | |
| Red-bellied newt LPXRFa-2 | MPHASANLPLRFa | |
| Red-bellied newt LPXRFa-3 | SIQPLANLPQRFa | |
| Red-bellied newt LPXRFa-4 | APSAGQFIQTLANLPQRFa | |
| Teleost fishes | Goldfish LPXRFa-3 | SGTGLSATLPQRFa |
| Agnathans | Sea lamprey LPXRFa-1a | SGVGQGRSSKTLFQPQRFa |
| Sea lamprey LPXRFa-1b | AALRSGVGQGRSSKTLFQPQRFa | |
| Sea lamprey LPXRFa-2 | SEPFWHRTRPQRFa | |
| Protochordates | Amphioxus PQRFa-1 | WDEAWRPQRFa |
| Amphioxus PQRFa-2 | GDHTKDGWRPQRFa | |
| Amphioxus PQRFa-3 | GRDQGWRPQRFa | |
Only mature endogenous peptides structurally determined by high-performance liquid chromatography and mass spectrometry are shown. Characteristic C-terminal sequences for GnIH peptides, -LPXRFamide (X = L or Q) sequences, are shown in bold.