[Leu31,Pro34]-Neuropeptide Y (porcine) is a high affinity neuropeptide Y Y1 receptor agonist (Ki = 0.54 nM).
This NPY analog is a highly potent and selective ligand for Y₁ receptors in different cell lines and tissues. It has therefore been used to detect the NPY/PYY receptor subtype distribution, e.g., in rat brain. The peptide is also active in vivo, showing an even higher potency than NPY in increasing blood pressure in anesthetized rats.