Oxytocin: Functions, Mechanism of Control, High Levels, Low Levels, Behavioral Effects, Drug Uses and Studies

It is a neurotransmitter and a hormone that is produced in the hypothalamus .

It is secreted into the bloodstream by the posterior pituitary gland.

The secretion depends on the electrical activity of neurons in the hypothalamus: it is released into the blood when these cells are excited.

Features

The two main actions of oxytocin in the body are the contraction of the uterus during labor and breastfeeding.

Oxytocin stimulates uterine muscle contraction and also increases prostaglandin production, further increasing contractions.

Oxytocin is sometimes given to induce labor if it has not started naturally or if it can be used to strengthen contractions to aid labor.

Additionally, oxytocin is often given to speed up delivery of the placenta and reduce the risk of heavy bleeding when contracting the uterus.

During lactation, oxytocin promotes the movement of milk into the breast, allowing the nipple to excrete.

Oxytocin is also present in men, playing a role in sperm movement and testosterone production in the testes.

In the brain , oxytocin acts as a chemical messenger and has been shown to be important in human behaviors, including sexual arousal, recognition, confidence, anxiety, and mother-child bonding.

As a result, oxytocin has been called the ‘love hormone’ or ‘cuddle chemical’.

Many research projects are conducted, looking at the role of oxytocin in addiction, brain injury, anorexia, and stress, among other topics.

How is oxytocin controlled?

Oxytocin is controlled by a positive feedback mechanism where the release of the hormone triggers an action that stimulates more of its own release.

When the uterus begins to contract, for example, oxytocin is released, which stimulates more contractions and releases more oxytocin. In this way, the contractions increase in intensity and frequency.

There is also a positive feedback involved in the milk ejection reflex. When a baby sucks on its mother’s breast, the stimulation leads to the secretion of oxytocin into the blood, which causes the milk to flow into the breast.

Oxytocin is also released in the brain to help stimulate oxytocin secretion. These processes are self-limited; hormone production stops after the baby is born or when the baby stops feeding.

What if I have too much oxytocin?

At present, the implications of having too much oxytocin are unclear.

High levels have been linked to benign prostatic hyperplasia, a condition that affects the prostate in more than half of men over the age of 50. This can cause difficulty passing urine.

It may be possible to treat this condition by manipulating oxytocin levels; however, more research is needed before possible treatments are available.

What if I have too little oxytocin?

Similarly, it is not fully understood at this time if there are implications of having too little oxytocin in the body.

Lack of oxytocin in a nursing mother would prevent the milk ejection reflex and prevent lactation.

Low levels of oxytocin have been linked to autism and autism spectrum disorders (eg, Asperger’s syndrome); a key element of these disorders is poor social functioning.

Some scientists believe that oxytocin could be used to treat these disorders.

Additionally, low oxytocin has been linked to depressive symptoms and has been proposed as a treatment for depressive disorders.

However, there is currently not enough evidence to support its use for any of these conditions.

The love hormone

In 2012, researchers reported that people in the early stages of romantic bonding had higher levels of oxytocin, compared to unconnected single people. These levels persisted for at least 6 months.

Sexual activity has been found to stimulate the release of oxytocin, and it appears to play a role in erection and orgasm.

The reason for this is not fully understood, but, in women, it is possible that increased uterine motility can help sperm reach their destination.

Some have proposed a correlation between oxytocin concentration and orgasm intensity.

Oxytocin and emotion

When oxytocin enters the bloodstream, it affects the uterus and lactation, but when it is released in certain parts of the brain, it can affect emotional, cognitive, and social behaviors.

A review of the research on oxytocin indicates that the hormone’s impact on “pro-social behaviors” and emotional responses contributes to relaxation, confidence, and psychological stability.

Cerebral oxytocin also appears to reduce responses to stress, including anxiety. These effects have been seen in several species.

The hormone has been described as “an important component of a complex neurochemical system that enables the body to adapt to highly emotional situations.”

Behavioral effects

Administration of oxytocin through a nasal spray has allowed researchers to observe its effects on behavior.

In 2011, research published in Psychopharmacology found that intranasal oxytocin improves self-perception in social situations and increases personality traits, such as warmth, trust, altruism, and openness.

In 2013, a study published in PNAS suggested that oxytocin can help keep men faithful to their partners, by activating reward centers in the brain.

In 2014, researchers published findings in the journal Emotion suggesting that people viewed the facial expression of emotions in others more intensely after receiving oxytocin through a nasal spray.

Oxytocin as a drug

Oxytocin is used as a prescription drug under the brand name Pitocin. Under medical supervision, an injection of oxytocin is sometimes used to start labor contractions or strengthen them during labor, and it helps reduce bleeding after delivery. Side effects include a fast heartbeat and unusual bleeding.

If too much oxytocin is given too quickly, it can cause the uterus to rupture.

Oxytocin can also be given to make the uterus contract and control bleeding after delivery or an interruption.

It can be used medically to induce a termination or complete a miscarriage.

psychiatric therapy

Oxytocin has been proposed as a possible treatment for social phobia, autism, and postpartum depression .

Scientists have proposed that it could help improve interpersonal and individual well-being, and that it could have applications for people with some neuropsychiatric disorders.

They believe it could help people who avoid social interaction, and those who experience persistent fear and an inability to trust others.

Children with autism could benefit from oxytocin, say some researchers. In 2013, a small study suggested that oxytocin levels in the brain affected how 17 children perceived a series of social and non-social images.

Oxytocin can also play a role in anger management. Research has indicated that certain polymorphisms of the oxytocin receptor gene (OXTR) are associated with an increased tendency to react angrily to situations.

In particular, differences in the expression of the OXTR gene appear to affect the regulation of the relationship between alcohol and aggressive behavior.

Applications

Oxytocin appears to increase the release of prostaglandin E2 (PGE2) in the cells that line the intestine. This helps promote intestinal injury repair and protect against such injuries.

If this is confirmed, oxytocin could be a useful therapy to prevent chemotherapy-induced bowel injury and could be used to treat irritable bowel syndrome (IBS).

Risks

The role of oxytocin is complex and not easy to pin down.

While it appears to improve bonding and community building, it can also encourage the formation of ‘groups’ and ‘outside groups’, leading to envy, prejudice, and possibly aggression.

Participants in a 2014 study were more likely to lie for the benefit of others in the same group after receiving oxytocin. The findings, the researchers said, could help “provide insight into when and why collaboration turns to corruption.”

More research is needed to understand the complexity of oxytocin and what it does.

Other studies

In 2006, researchers reported that they found higher levels of oxytocin and cortisol among women who had “gaps in their social relationships” and more negative relationships with their main partner. All participants received hormone therapy (HT) after menopause.

Animal studies have found high levels of stress and oxytocin in mice that were separated from other camps.

However, when the mice were given doses of oxytocin, their levels of anxiety, cardiac stress and depression decreased, suggesting that stress increases internal production of the hormone, while externally supplied doses may help reduce the stress.

Clearly, the action of oxytocin is not direct.

A review published in 2013 cautions that oxytocin is likely to have general rather than specific effects, and that oxytocin alone is not likely to affect “complex, high-order mental processes that are specific to social cognition.”

The authors also note that the willingness to collaborate is likely to be driven by anxiety in the first place.

However, oxytocin appears to be associated with social behavior, including maternal care, relationships between partners, sexual behavior, social memory, and trust.