This is the rat form of 26RFa (QRFP), the hypothalamic RFamide peptide that signals through GPR103. Comparing the supplied rat and human sequences shows they diverge at several positions across the N-terminal and central regions while sharing an identical C-terminal GGFSFRF-amide, the motif that the receptor recognises. That pattern, a conserved business end on a variable body, is characteristic of the RFamide family and has a direct practical consequence: antibodies raised against the whole peptide may distinguish the species, while those directed at the C-terminus will not. For quantifying endogenous peptide in rat tissue or plasma, a species-matched standard is therefore the safer choice, and cross-reactivity should be established rather than assumed. The rat sequence is also the appropriate reagent for in vivo work in that species, which is where much of the feeding literature was generated. Central administration of QRFP increases food intake, with a preference reported for high fat food in rats specifically, and effects extend to locomotor activity. Using the homologous peptide avoids the differing clearance and potential immune recognition that a foreign sequence can introduce over repeated dosing. | 