Oxytocin is a powerful hormone. When we hug or kiss a loved one, oxytocin levels drive up. It also acts as a neurotransmitter in the brain. In fact, the hormone plays a huge role in pair bonding. Prairie voles, one of nature’s most monogamous species, produce oxytocin in spades. This hormone is also greatly stimulated during sex.
In two papers published in 1987 and 1994, Marie Carmichael and colleagues reported that increases in circulating levels of oxytocin accompany orgasm in both men and women. Levels area;so markedly raised with orgasm attained through self-stimulation and the raised levels persist for several minutes.
Oxytocin is a neuropeptide “touch” hormone that is secreted during human and animal interpersonal touch and sexual arousal, particularly at orgasm. Oxytocin strongly stimulates sexual responses in both female and male animals. In rats, oxytocin stimulates penile erection through an increase in nitric oxide. As with sildenafil and apomorphine, female genital vasodilatation would be increased by induction of a nitric oxide mechanism. It should be noted that oxytocin is activated by the presence of estrogen, so that postmenopausal estrogen replacement therapy may resolve a menopausal oxytocin-deficiency state.