[Phylogeny of neurohypophyseal hormones in birds: microidentification of mesotocin and vasotocin in the ostrich (Struthio camelus)].

Ostrich (Struthio camelus) neurohypophysial hormones have been isolated from 5 freeze-dried posterior pituitary glands. Purification has involved three steps: a first molecular sieving on Sephadex G-75 for eliminating proteins, a second molecular sieving on Bio-Gel P4 for separating the two active principles and a high pressure reverse-phase liquid chromatography (HPLC) on Nova-Pak C 18 with an 10 mM acetate-acetonitrile gradient for isolating each hormone. The active peptides have been identified by their retention time in HPLC and their amino acid composition. Mesotocin and vasotocin have thus been characterized. Although the phylogeny of Ratites is disputed, in particular their possible common origin with Carinates, which include most of the living birds, species of the first sub-class seem to have the same neurohypophysial hormones as those of the second.