Y4 may refer to: *

Pancreatic polypeptide receptor 1 Pancreatic polypeptide receptor 1, also known as Neuropeptide Y receptor type 4, is a protein that in humans is encoded by the ''PPYR1'' gene. Selective Ligands Agonists * Pancreatic polypeptide * Neuropeptide Y (endogenous agonist, non subtype s ...

, a protein that in humans is encoded by the ''PPYR1'' gene * a Mazda diesel engine *

IATA airline designator This is a list of airline codes. The table lists IATA's two-character airline designators, ICAO's three-character airline designators and the airline call signs (telephony designator). Historical assignments are also included.ht IATA airline ...

for

Volaris Volaris, legally ''Concesionaria Vuela Compañía de Aviación S.A.P.I. de C.V.'', is a Mexican low-cost airline based in Santa Fe (Mexico City), Santa Fe, Álvaro Obregón, D.F., Álvaro Obregón, Mexico City l-888-Ʒ9Ʒ-I394 with its hubs in M ...

* LNER Class Y4, a class of British steam

See also