MESOTOCIN AND OXYTOCIN IN THE BRAIN AND PLASMA OF AN AUSTRALIAN MARSUPIAL, THE NORTHERN BROWN BANDICOOT, ISOODON-MACROURUS

Abstract

1. Mesotocin (MT) and oxytocin (OT) were measured in the brain and plasma of bandicoots using reverse phase high performance liquid chromatography and specific radioimmunoassays. 2. MT and OT were found in the pituitary (1.25 +/- 0.10 micrograms/MT; 0.725 +/- 0.077 micrograms/OT) and hypothalamus (38.37 +/- 6.46 ng/MT; 19.1 +/- 4.61 ng/OT). Smaller amounts were present in the cerebral cortex. 3. Basal plasma concentrations ranged from 1.5 to 8.1 pg/ml for both peptides (N = 14) and were elevated by stress. 4. It was concluded that both MT and OT are secreted by the bandicoot brain and that stress stimulates secretion.