Enables neuropeptide hormone activity and oxytocin receptor binding activity. Involved in several processes, including mating; positive regulation of smooth muscle contraction; and regulation of secretion. Located in extracellular space; secretory granule; and terminal bouton. Used to study gastric ulcer and hypertension. Biomarker of hypertension. Orthologous to human OXT (oxytocin/neurophysin I prepropeptide). [provided by Alliance of Genome Resources, Apr 2022]