Peptide directoryBrain, hypothalamus & pituitary

Phoenixin-14

A peptide found by genome search in 2013, a tuner of reproduction and mood.

Where it comes from

Made in
Hypothalamus, pituitary, spinal cord, heart and gut
Sent out by
The oestrous cycle in rodents; feeding
Acts on
  • Pituitary gonadotrophs (GnRH receptor expression)
  • Hypothalamus (anxiety, feeding)
  • Skin (itch)
  • Heart

What it does

  • Makes the pituitary more responsive to GnRH; silencing it in rats delays oestrus and lowers pituitary GnRH receptor levels 1
  • Lowers anxiety and raises food intake in rodents 2
  • Provokes scratching when injected under the skin of mice 4

In medicine

  • No medicine copies it or blocks it. Blood phoenixin is a research marker in polycystic ovary syndrome and obesity, with no agreed assay behind it 2
  • Its proposed receptor, GPR173, is still an orphan by the usual standards, which is why nothing has been built on it 2

Beyond the body’s own use

  • Nothing containing phoenixin is in trials, approved or obtainable outside the laboratory
  • The gene-deletion result argues against most of what is claimed for it: mice without phoenixin breed normally, handle a high-fat diet like any other mouse, and differ only in behaviour in an open field 3
  • Its one clear effect in skin is unwelcome. Injected under the skin of a mouse it provokes scratching, which makes it a candidate itch signal rather than a treatment for anything 4

Sources

  1. Yosten et al., A novel reproductive peptide, phoenixin, Journal of Neuroendocrinology 2013
  2. Stein et al., The phoenixins, from discovery of the hormone to identification of the receptor, Peptides 2018
  3. McIlwraith et al., Phoenixin knockout mice show no impairment in fertility or metabolic response to a high-fat diet, Journal of Neuroendocrinology 2024
  4. Cowan et al., Phoenixin, a candidate pruritogen in the mouse, Neuroscience 2015

This card describes what a medicine is for and what the evidence says; it recommends nothing. Talk to your clinician about anything you read here.