Mechanism of Action
GPR173 Activation
Phoenixin-14 activates GPR173, a Gs-coupled orphan GPCR highly expressed in the hypothalamus and limbic structures. Receptor activation increases cAMP and activates PKA, modulating neuronal excitability and gene expression. GPR173 is expressed in GnRH neurons, kisspeptin neurons, and amygdala circuits, positioning phoenixin as a regulator of reproductive and emotional circuits.
GnRH Neuronal Effects
Phoenixin-14 potentiates GnRH neuron sensitivity to kisspeptin stimulation, increasing GnRH pulsatility and LH secretion in rodent models. It also upregulates GnRH receptor expression in pituitary gonadotrophs, amplifying the gonadotropin response. This dual action positions phoenixin as a positive modulator of the kisspeptin-GnRH-LH axis.
Research Summary
Anxiety Reduction
PreclinicalCentral administration of phoenixin-14 reduces anxiety-like behavior in the elevated plus maze and open field test in rodents. Repeated administration produces anxiolytic effects that persist beyond the dosing period. The amygdala and hippocampus are key sites of action, where phoenixin modulates GABAergic inhibitory tone.
Reproductive Axis Modulation
PreclinicalPhoenixin-14 increases LH pulsatility and accelerates puberty onset in female rodents. Its expression in the hypothalamus is regulated by estradiol and metabolic state, suggesting integration of hormonal and nutritional signals to regulate fertility. Phoenixin may complement kisspeptin in activating the HPG axis.
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Research Protocols
| Goal | Dose | Frequency | Route |
|---|---|---|---|
| Anxiety models | 1-10 nmol ICV | Single | Intracerebroventricular |
| LH release | 10-100 nmol SC | Single | Subcutaneous |
Preclinical only. No human safety or clinical data for phoenixin.
Interactions
Safety Profile
Phoenixin-14 is an endogenous neuropeptide with a favorable preclinical safety profile. No adverse effects identified at effective doses in rodent models. Human safety data absent; no clinical trials conducted.
References
- [1]Yosten GL et al. (2013). Evidence for an interaction between phoenixin and nesfatin-1 in the regulation of luteinizing hormone secretion in female rats. American Journal of Physiology, Regulatory, Integrative and Comparative Physiology, 304(11), R1060-R1067.
- [2]Stein LM et al. (2016). Novel peptide phoenixin: an emerging regulator of feeding and anxiety. Peptides, 77, 31-36.