Causes contractions. Vasopressin causes constriction and contraction of the small blood vessels (arterioles). Oxytocin cause contractions of the smooth muscle of the uterus. Both of these entities are made in a place some distance form their target organs but are very effective in the job they do.
More than we thought. For 100yrs oxytocin's role was believed to mainly involve empowering contractions in labor. Also some role in lactation "let-down".Recently found to help people connect w/ others emotionally & also decrease anxiety. Both effects make it ripe for study in autism, schizophrenia, etc. Those studies are starting & I've begun rxing it. Similar chemically, vasopressin mainly concentrates urine-& maybe more?