Storage Stability
QRFP (also called 26RFa) is a C-terminally amidated RFamide neuropeptide first identified in frog brain and subsequently in mammals. It exists in two biologically active forms: the 26-amino-acid 26RFa and the 43-amino-acid QRFP-43. Both forms act at GPR103 (QRFP receptor) and potently stimulate food intake, adipogenesis, and aldosterone secretion.
Mechanism of Action
- GPR103 is a Gq-coupled receptor; QRFP binding mobilizes intracellular calcium and activates MAPK/ERK pathways
- Central orexigenic: ICV QRFP/26RFa is among the most potent orexigenic peptides, increasing 24-hour food intake up to 3-fold
- Promotes adipocyte differentiation and lipid accumulation via GPR103 expressed on preadipocytes
- Stimulates aldosterone secretion from adrenal cortex via GPR103, establishing a link between hypothalamic circuits and adrenal function
- Regulates bone metabolism: GPR103 knockout mice have reduced bone density, suggesting a QRFP-mediated trophic bone signal
Research Findings
- 26RFa originally identified in frog (Rana esculenta) hypothalamus as potent feeding stimulant; mammalian orthologs confirmed shortly after
- GPR103 knockout mice are lean with reduced adiposity despite normal caloric intake, suggesting altered energy partitioning rather than hypophagia
- High-fat diet increases hypothalamic QRFP mRNA expression, suggesting a potential role in diet-induced obesity
- QRFP promotes adrenocortical cell survival and is a potent aldosterone secretagogue; potential role in primary aldosteronism
- GPR103 expressed in bone; QRFP stimulates osteoblast differentiation and bone formation in cell cultures
Research Protocols
- ICV injection: 1-10 nmol 26RFa or QRFP-43 in fasted rodents for acute food intake measurement over 1-4 hours
- GPR103 binding assay: QRFP at 0.1-100 nM; Kd ~2-5 nM for human GPR103
- In vitro adipogenesis: 1-100 nM QRFP during 3T3-L1 differentiation protocol; assess lipid droplet formation
- Adrenal secretion: 1-100 nM QRFP on primary adrenocortical cells; measure aldosterone by RIA
Interactions
- Orexin-A and NPY: all three are potent hypothalamic orexigens; QRFP may synergize with NPY at hypothalamic level
- GPR103 antagonists: investigational tool compounds (no clinical-stage antagonist yet); needed to define therapeutic relevance
- MC4R pathway: QRFP and MC4R agonists (alpha-MSH) have opposing effects on food intake; QRFP may modulate melanocortin tone
Safety Profile
Endogenous neuropeptide. Not used therapeutically. Central QRFP increases food intake and adiposity; antagonism is the therapeutic direction for obesity, not agonism. GPR103 antagonists in early preclinical stage.
Legal & Regulatory
Research peptide; not approved as therapeutic
Ready to dose QRFP (26RFa)?
Get the exact syringe draw
You have read the research. Now run the math. Pick your vial size and BAC water volume, get IU draw in seconds.
Open the Calculator →
More in Weight Loss & Metabolic
View all →