Carraway R E, Cochrane D E, Mitra S P
Department of Physiology, University of Massachusetts Medical Center, Worcester 01605.
Regul Pept. 1988 Sep;22(4):303-14. doi: 10.1016/0167-0115(88)90107-3.
Two avian counterparts to amphibian xenopsin have been identified as H-Phe-His-Pro-Lys-Arg-Pro-Trp-Ile-Leu-OH (XP-2) and its partial sequence H-His-Pro-Lys-Arg-Pro-Trp-Ile-Leu-OH (XP-1) isolated from extracts of turkey proventriculus and skin. Both peptides were shown to be present within these and other tissues primarily (99%) in precursor form(s), from which they were liberated by the action of endogenous enzyme(s) during extraction. Synthetic and native preparations of XP-2 increased vascular permeability in rats and released histamine from isolated rat mast cells at submicromolar concentrations. The ubiquitous distribution of this XP-related sequence and its pharmacologic capabilities suggest potential roles in the general regulation of tissue blood flow and fluid exchange.
