Oxytocin
Oxytocin is a hormone found in the human body. It is secreted by the posterior lobe of the pituitary gland. Oxytocin is composed of nine amino acids arranged as a ring, which is formed by the linkage of two molecules of the amino acid cystine and a short side chain. It is classified as a peptide hormone.
Secretion and Production
Oxytocin is produced in the magnocellular neurosecretory cells in the supraoptic nucleus and paraventricular nucleus of the hypothalamus and is released into the blood from the posterior lobe of the pituitary gland. Its primary effects are the promotion of urine concentration (in collaboration with arginine vasopressin), the inducement of contractions during labor, and the release of breast milk during suckling.
Oxytocin is secreted by both males and females during orgasm. In males, oxytocin may facilitate sperm transport in ejaculation.
Pharmacological Uses
Synthetic oxytocin must be administered by injection or as a nasal spray. Its primary use as a drug is to induce labor in cases of both pregnancies extending dangerously beyond their due dates and planned caesarian sections. Additionally, it is commonly used to increase uterine tone in acute postpartum hemorrhage.