MARSUPIAL HYPOTHALAMO-NEUROHYPOPHYSEAL HORMONES - THE BRUSH-TAILED POSSUM (TRICHOSURUS-VULPECULA) ACTIVE PEPTIDES

  • 1 January 1982
    • journal article
    • research article
    • Vol. 19  (4) , 366-371
Abstract
The hypothalamo-neurohypophyseal hormones of the brush-tailed possum (T. vulpecula) were purified through molecular sieving and paper chromatoelectrophoresis. Two peptides were isolated, one with pressor property, the other with uterotonic activity. The pressor hormone was identified as arginine vasopressin by amino acid composition and amino acid sequence. The oxytocin-like hormone was characterized as mesotocin by amino acid composition. The amounts per dried neuro-intermediate gland (1.0-1.5 mg) are .apprx. 12 and 5 nmol, respectively. Up to now, mesotocin has only been found in non-mammalian tetrapods, particularly in reptiles. Its preservation in Australian marsupials (Macropodidae and Phalangeridae), and the replacement of vasotocin by a vasopressin-like peptide, suggests that they are transition species between reptiles and Eutheria. The presence of mesotocin raises the question of its role in marsupial lactation.