Sexual motivation is influenced by hormones such as testosterone, estrogen, progesterone, oxytocin, and vasopressin. Other hormones secreted from the median eminence include vasopressin, oxytocin, and neurotensin. Two hormones are classically considered as being related to the posterior pituitary&colon; oxytocin and vasopressin. The stimulation of a woman's nipples promotes the production and release of oxytocin and prolactin. The structure of oxytocin is very similar to that of vasopressin. The first major breakthrough was the synthetic production of oxytocin and vasopressin in 1961. The peripheral actions of oxytocin mainly reflect secretion from the pituitary gland. This process is primarily due to the hormone oxytocin. Its actions are mediated by specific oxytocin receptors. Orally administered misoprostol was marginally less effective than oxytocin. They varied empathy by infusing participants with intranasal oxytocin or placebo (blinded). Misoprostol also may be used in conjunction with oxytocin. A surge of oxytocin also causes the uterus to contract. Misoprostol may be used in areas where oxytocin is not available. Positive social interaction is associated with increased oxytocin.