Oxytocin

oxytocicsfirst synthesis of a polypeptide hormoneBonding in mammalsOXToxytocicOxytocin (OT)oxytocin (OXT)receptors, oxytocin
Oxytocin (Oxt) is a peptide hormone and neuropeptide.wikipedia
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Oxytocin (medication)

oxytocinpitocinSyntocinon
Oxytocin is also used as a medication to facilitate childbirth.
Oxytocin, sold under the brand name Pitocin among others, is a medication made from the peptide oxytocin.

Hypothalamus

hypothalamicanterior hypothalamushypothalamic hormones
Oxytocin is normally produced in the hypothalamus and released by the posterior pituitary. In the hypothalamus, oxytocin is made in magnocellular neurosecretory cells of the supraoptic and paraventricular nuclei, and is stored in Herring bodies at the axon terminals in the posterior pituitary.
In mammals, magnocellular neurosecretory cells in the paraventricular nucleus and the supraoptic nucleus of the hypothalamus produce neurohypophysial hormones, oxytocin and vasopressin.

Breastfeeding

breast feedingbreastfeedbreast-feeding
Oxytocin is released into the bloodstream as a hormone in response to stretching of the cervix and uterus during labor and with stimulation of the nipples from breastfeeding.
Oxytocin contracts the smooth muscle of the uterus during birth and following delivery, called the postpartum period, while breastfeeding.

Lactation

lactatinglactatenurse
This helps with birth, bonding with the baby, and milk production.
Oxytocin is critical for the milk let-down reflex in response to suckling.

Oxytocinase

Oxytocin is known to be metabolized by the oxytocinase, leucyl/cystinyl aminopeptidase.
Oxytocinase is a type of enzyme that metabolizes the endogenous neuropeptide, oxytocin.

Human bonding

bondingbondsocial bonding
It plays a role in social bonding, sexual reproduction, childbirth, and the period after childbirth.
The maternal bond begins to develop during pregnancy; following pregnancy, the production of oxytocin during lactation increases parasympathetic activity, thus reducing anxiety and theoretically fostering bonding.

Paraventricular nucleus of hypothalamus

paraventricular nucleusparaventricular hypothalamic nucleusparaventricular
In the hypothalamus, oxytocin is made in magnocellular neurosecretory cells of the supraoptic and paraventricular nuclei, and is stored in Herring bodies at the axon terminals in the posterior pituitary.
Many PVN neurons project directly to the posterior pituitary where they release oxytocin into the general circulation.

Estradiol

17β-estradioloestradiol17-β-estradiol
In women, a single dose of estradiol has been found to be sufficient to increase circulating oxytocin concentrations.
They may promote uterine blood flow, myometrial growth, stimulate breast growth and at term, promote cervical softening and expression of myometrial oxytocin receptors.

Estrogen

oestrogenestrogensestrogenic
Estrogen has been found to increase the secretion of oxytocin and to increase the expression of its receptor, the oxytocin receptor, in the brain.

Orgasm

sexual gratificationfemale orgasmclimax
Studies have looked at oxytocin's role in various behaviors, including orgasm, social recognition, pair bonding, anxiety, in-group bias, situational lack of honesty, autism, and maternal behaviors.
The period after orgasm (known as the refractory period) is often a relaxing experience, attributed to the release of the neurohormones oxytocin and prolactin as well as endorphins (or "endogenous morphine").

Neurohypophysial hormone

neurohypophysial
The finding of significant amounts of this classically "neurohypophysial" hormone outside the central nervous system raises many questions regarding its possible importance in these different tissues.
Their main representatives are oxytocin and vasopressin.

Leucyl/cystinyl aminopeptidase

cystinyl aminopeptidaseinsulin-regulated aminopeptidaseLNPEP
Oxytocin is known to be metabolized by the oxytocinase, leucyl/cystinyl aminopeptidase.
This gene encodes a zinc-dependent aminopeptidase (metalloexopeptidase) that cleaves vasopressin, oxytocin, lys-bradykinin, met-enkephalin, dynorphin A and other peptide hormones.

Neurophysin I

This precursor protein also includes the oxytocin carrier protein neurophysin I.
It is a neurohypophysial hormone that is transported in vesicles with oxytocin, the other cleavage product, along axons, from magnocellular neurons of the hypothalamus to the posterior lobe of the pituitary.

Prostaglandin F2alpha

prostaglandin F 2α PGF2alphadinoprost
Along with estrogen, it is involved in inducing the endometrial synthesis of prostaglandin F 2α to cause regression of the corpus luteum.
In domestic mammals, it is produced by the uterus when stimulated by oxytocin, in the event that there has been no implantation during the luteal phase.

Magnocellular neurosecretory cell

magnocellular neuronsmagnocellular neurosecretory neuronmagnocellular neurosecretory neurons
In the hypothalamus, oxytocin is made in magnocellular neurosecretory cells of the supraoptic and paraventricular nuclei, and is stored in Herring bodies at the axon terminals in the posterior pituitary.
There are two types of magnocellular neurosecretory cells, oxytocin-producing cells and vasopressin-producing cells, but a small number can produce both hormones.

Neuropeptide

neuropeptidesneuroactive dipeptideneuroactive peptide
Oxytocin (Oxt) is a peptide hormone and neuropeptide.
For example, oxytocin and vasopressin have striking and specific effects on social behaviours, including maternal behaviour and pair bonding.

Vasopressin

antidiuretic hormoneADHarginine vasopressin
Amastatin, bestatin (ubenimex), leupeptin, and puromycin have been found to inhibit the enzymatic degradation of oxytocin, though they also inhibit the degradation of various other peptides, such as vasopressin, met-enkephalin, and dynorphin A.
The structure of oxytocin is very similar to that of the vasopressins: It is also a nonapeptide with a disulfide bridge and its amino acid sequence differs at only two positions (see table below).

Mammary gland

mammaemammary glandsmammary
The myoepithelial cells contract under the stimulation of oxytocin, excreting the milk secreted by alveolar units into the lobule lumen toward the nipple.

Pair bond

pair bondingpair-bondingmate for life
Studies have looked at oxytocin's role in various behaviors, including orgasm, social recognition, pair bonding, anxiety, in-group bias, situational lack of honesty, autism, and maternal behaviors.
Peptide arginine vasopressin (AVP), dopamine, and oxytocin act in this region to coordinate rewarding activities such as mating, and regulate selective affiliation.

Amastatin

Amastatin, bestatin (ubenimex), leupeptin, and puromycin have been found to inhibit the enzymatic degradation of oxytocin, though they also inhibit the degradation of various other peptides, such as vasopressin, met-enkephalin, and dynorphin A.
Amastatin has been found to potentiate the central nervous system effects of oxytocin and vasopressin in vivo.

Childbirth

laborbirthlabour
Oxytocin is also used as a medication to facilitate childbirth. It plays a role in social bonding, sexual reproduction, childbirth, and the period after childbirth.
During the later stages of gestation there is an increase in abundance of oxytocin, a hormone that is known to evoke feelings of contentment, reductions in anxiety, and feelings of calmness and security around the mate.

Pituitary gland

pituitaryhypophysishypophysis cerebri
It is then released into the blood from the posterior lobe (neurohypophysis) of the pituitary gland.

Peptide hormone

peptide hormonesprotein hormonepolypeptide hormone
Oxytocin (Oxt) is a peptide hormone and neuropeptide.

Herring bodies

In the hypothalamus, oxytocin is made in magnocellular neurosecretory cells of the supraoptic and paraventricular nuclei, and is stored in Herring bodies at the axon terminals in the posterior pituitary.
Antidiuretic hormone (ADH) and oxytocin are both stored in Herring bodies, but are not stored simultaneously in the same Herring body.

Ubenimex

bestatinubenimix
Amastatin, bestatin (ubenimex), leupeptin, and puromycin have been found to inhibit the enzymatic degradation of oxytocin, though they also inhibit the degradation of various other peptides, such as vasopressin, met-enkephalin, and dynorphin A.
Ubenimex has been found to inhibit the enzymatic degradation of oxytocin, vasopressin, enkephalins, and various other peptides and compounds.