Oxytocin - Synthesis, Storage, and Release

Synthesis, Storage, and Release

Oxytocin, prepropeptide
Identifiers
Symbols OXT; OT; OT-NPI
External IDs OMIM: 167050 MGI: 97453 HomoloGene: 55494 GeneCards: OXT Gene
Gene Ontology
Molecular function neurohypophyseal hormone activity
oxytocin receptor binding
Cellular component extracellular region
extracellular space
secretory granule
terminal button
Biological process response to amphetamine
regulation of heart rate
maternal aggressive behavior
signal transduction
elevation of cytosolic calcium ion concentration
heart development
female pregnancy
memory
grooming behavior
response to sucrose stimulus
positive regulation of norepinephrine secretion
response to activity
sleep
positive regulation of prostaglandin secretion
response to estradiol stimulus
response to retinoic acid
response to progesterone stimulus
response to prostaglandin E stimulus
social behavior
negative regulation of urine volume
positive regulation of renal sodium excretion
response to cocaine
hyperosmotic salinity response
maternal behavior
sperm ejaculation
eating behavior
drinking behavior
response to peptide hormone stimulus
response to ether
negative regulation of blood pressure
positive regulation of blood pressure
positive regulation of ossification
positive regulation of female receptivity
positive regulation of synaptic transmission
response to glucocorticoid stimulus
response to cAMP
response to electrical stimulus
regulation of sensory perception of pain
positive regulation of synapse assembly
male mating behavior
positive regulation of penile erection
positive regulation of hindgut contraction
negative regulation of gastric acid secretion
positive regulation of uterine smooth muscle contraction
Sources: Amigo / QuickGO
Orthologs
Species Human Mouse
Entrez 5020 18429
Ensembl ENSG00000101405 ENSMUSG00000027301
UniProt P01178 P35454
RefSeq (mRNA) NM_000915.2 NM_011025.3
RefSeq (protein) NP_000906.1 NP_035155.1
Location (UCSC) Chr 20:
3.05 – 3.05 Mb
Chr 2:
130.58 – 130.58 Mb
PubMed search

The oxytocin peptide is synthesized as an inactive precursor protein from the OXT gene. This precursor protein also includes the oxytocin carrier protein neurophysin I. The inactive precursor protein is progressively hydrolyzed into smaller fragments (one of which is neurophysin I) via a series of enzymes. The last hydrolysis that releases the active oxytocin nonapeptide is catalyzed by peptidylglycine alpha-amidating monooxygenase (PAM).

The activity of the PAM enzyme system is dependent upon vitamin C (ascorbate), which is a necessary vitamin cofactor. By chance, sodium ascorbate by itself was found to stimulate the production of oxytocin from ovarian tissue over a range of concentrations in a dose-dependent manner. Many of the same tissues (e.g. ovaries, testes, eyes, adrenals, placenta, thymus, pancreas) where PAM (and oxytocin by default) is found are also known to store higher concentrations of vitamin C.

Read more about this topic:  Oxytocin

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