Oxytocin, also referred to as the love hormone, is one of the more commonly known peptides. Oxytocin naturally occurs in the hypothalamus and is released through the pituitary gland.
Additionally, the main role of oxytocin is to facilitate childbirth and lactating by promoting contraction of the uterus, as well as let-down of milk supply.
Furthermore, when oxytocin is released in various situations such as cuddling an animal or hugging a loved one, serotonin is released in the brain. Researchers Uvnäs-Moberg et. Al explored the link between oxytocin and depression in male Sprague-Dawley rats. The study examined how 20 mg/kg IP of the SSRI, citalopram, affects levels of plasma oxytocin.