Home > Oxytocin

1 Structure

Oxytocin is a peptide of nine amino acids (a nonapeptide). The sequence is cysteine - tyrosine - isoleucine - glutamine - asparagine - cysteine - proline - leucine - glycine. The leucine is the only difference from anti-diuretic hormone, which has arginine or lysine at this position. The cysteine residues form a sulfur bridge.

2 Functions

Functions of oxytocin:

• milk letdown -- in lactating mothers, oxytocin stimulates myoepithelial cells , causing milk to be ejected into the ducts of the mammary glands. Sucking by the infant at the nipple stimulates oxytocin release.
• uterine contraction -- necessary for cervical dilatation prior to birth and causes the contractions all mothers are familiar with. Oxytocin release during breastfeeding causes mild but often painful uterine contractions during the first few weeks of lactation.
• Inducing maternal behaviour -- Sheep and rat females given oxytocin antagonists after giving birth do not exhibit typical maternal behavior such as grooming towards newborns. Conversely, virgin sheep females show maternal behavior towards foreign lambs upon cerebrospinal fluid infusion of oxytocin, which they would not do otherwise.
• Plays some role in orgasms -- for both males and females. In males, oxytocin is said to facilitate sperm transport in ejaculation.
• Thought to induce pair bonding in people. Levels of oxytocin are found to be higher amongst people who claim to be falling in loveFor the 1960s band, see Love (band). The term is also used in tennis. Love has many meanings in English. It can mean an intense feeling of affection, an emotion or emotional state. In ordinary use, it usually refers to interpersonal love. Love is one of t. It is also thought to mediate other forms of pair bonding such as friendship and family relationships as given above.

3 Therapeutic use

Oxytocin analogues ( pitocinPitocin is the synthetic version of the hormone oxytocin, which is produced by pregnant women to cause the uterine contractions that precipitate childbirth. Pitocin is administered if a doctor determines that, for any of a number of reasons, labor needs t, Syntocinon®) are used to induce labour and support labour in case of non-progression of the parturition. It has largely replaced ergotamine as the principal agent to increase uterine tone in acute postpartum haemorrhage.

An oxytocin nose spray may be a useful adjunct to stimulate breastfeeding.

Inhibition of oxytocin action is the mode of action of the new tocolytic agent atosiban (Tractocile®), which is registered in many countries to suppress premature labour between 24 and 33 weeks of gestation. It has fewer side-effects than drugs previously used for this purpose ( ritodrine , salbutamolSalbutamol ( INN) or albuterol ( USAN) is a short-acting β-adrenergic receptor agonist used for the relief of bronchospasm in conditions such as asthma and COPD. It is marketed by the Allen & Hanbury's respiratory division of GlaxoSmithKline under th and terbutaline).