[Asp5]-Oxytocin is the first 5-position neurohypophyseal hormone analogue possessing significant biological activity. [Asp5]-Oxytocin causes uterine contractions in vitro, enhanced by Mg 2+. [Asp5]-Oxytocin has the ability of rat uteroconstrictor, avian vasodilator, and rat antidiuretic. In Vitro [Asp5]-Oxytocin retains not only a high affinity for the uterotonic receptor, but also an intrinsic activity identical with that of oxytocin. [Asp5]-Oxytocin displays an increasing intrinsic activity enhanced by 1 mM Mg 2+. [Asp5]-Oxytocin exerts the same potencies of rat uterotonic, avian vasodepressor, and rat antidiuretic with 20.3, 41, and 0.14 units/mg dose. MCE has not independently confirmed the accuracy of these methods. They are for reference only. Form:Solid