Marsupial neurohypophysial hormones: identification of mesotocin, lysine vasopressin, and phenypressin in the quokka wallaby (Setonix brachyurus)

Abstract

The neurohypophysial hormones of the quokka wallaby (Setonix brachyurus) have been isolated through preparative high pressure liquid chromatography (HPLC). One oxytocin-like and two vasopressin-like peptides have been found. These peptides have been characterized by their amino acid composition and by their retention time in HPLC. Mesotocin ([I1e8]-oxytocin) has been identified by amino acid composition, polar partition chromatography, high pressure liquid chromatography with a reversed phase column, and pharmacological properties. Lysine vasopressin and phenypressin ([Phe2]-arginine vasopressin) have been characterized by amino acid composition, ion-exchange chromatography, and high pressure liquid chromatography. Lysine vasopressin is about twice as abundant as phenypressin. These three peptides have previously been found in three species belonging to the genus Macropus, namely the red kangaroo, the Eastern gray kangaroo, and the tammar wallaby; they are therefore current in the family Macropodidae. Comparison with other native Australian mammals is discussed.