Peptide directoryBrain, hypothalamus & pituitary

PHM-27

VIP’s companion from the same precursor, the human form of PHI.

Where it comes from

Made in
The same neurons as VIP in gut, brain, airway and pituitary stalk
Sent out by
With VIP
Acts on
  • Smooth muscle
  • Pituitary lactotrophs
  • Pancreas

What it does

  • Relaxes smooth muscle and stimulates secretion like VIP 1
  • Releases prolactin, but less powerfully than VIP: in matched infusions in people, only VIP raised it 2
  • Secreted by VIPomas alongside VIP, often at higher blood levels 3

In medicine

  • Measured in research with VIP. In people with VIP-secreting tumours it is raised in plasma, often above VIP itself, but it is not part of any routine test 3
  • No medicine copies it or blocks it. The VIP receptor drugs in development are aimed at VPAC1 and VPAC2 without regard to which of the two peptides normally reaches them

Beyond the body’s own use

  • Nothing containing PHM-27 is in trials, approved or obtainable outside the laboratory
  • The one direct human experiment is informative: infused at matched doses in volunteers, VIP raised prolactin and PHM-27 did not, so two peptides released from the same nerve are not interchangeable 2
  • What is unknown is why the body makes both. One precursor yields VIP and PHM-27 together, their receptor preferences are reversed, and no condition is known in which the balance between them is shifted on purpose 1

Sources

  1. Itoh et al., Human preprovasoactive intestinal polypeptide contains a novel PHI-27-like peptide, PHM-27, Nature 1983
  2. Yiangou et al., Infusion of prepro-VIP derived peptides in man, effect on prolactin secretion, Neuroendocrinology 1988
  3. Yiangou et al., Peptide histidine-methionine in plasma and tissue from patients with VIP-secreting tumours, Journal of Clinical Endocrinology and Metabolism 1987

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.