Oxytocin Molecule Necklace
Science symbols on cleavage, jockeys mount and nerds stare. 科学符号缀乳沟，莽汉上弓书呆瞪。
Oxytocin (Oxt) /ˌɒksɨˈtoʊsɪn/ is a mammalian neurohypophysial hormone that acts primarily as a neuromodulator in the brain.
Oxytocin plays roles in sexual reproduction, in particular during and after childbirth. It is released in large amounts after distension of the cervix and uterus during labor, facilitating birth, maternal bonding, and, after stimulation of the nipples, breastfeeding. Both childbirth and milk ejection result from positive feedback mechanisms.
Recent studies have begun to investigate oxytocin's role in various behaviors, including orgasm, social recognition, pair bonding, anxiety, and maternal behaviors. For this reason, it is sometimes referred to as the “love hormone”. There is some evidence that oxytocin promotes ethnocentric behavior, incorporating the trust and empathy of in-groups with their suspicion and rejection of outsiders. Furthermore, genetic differences in the oxytocin receptor gene (OXTR) have been associated with maladaptive social traits such as aggressive behaviour.