147492-03-3 4-Ser-8-ile-oxytocin 4-Serine-8-isoleucine-oxytocin 4294-14-8 550-21-0 Oxytocin, 4-L-serine-8-L-isoleucine- Oxytocin, ser(4)-ile(8)- Oxytocin, seryl(4)-isoleucine(8)- isotocin