Oxytocin

BeschreibungOxytocin is a peptide hormone containing nine amino acids secreted and synthesized by the paraventricular and supraoptic nuclei of the hypothalamus and stored and released by the neurohypophysis. It acts in females by inducing uterine contractions during parturition and stimulating milk ejection by the mammary glands. No actions in males are known. Synthetic derivatives of oxytocin are used to induce labor and for therapeutic abortions. In recent years the safety of oxytocin has been greatly enhanced by the use of continuous maternal and fetal monitoring and by the use of controlled intravenous infusion of the drug.

HistoryOxytocin was discovered by Sir Henry Dale in 1909 when he found that an extract from the human posterior pituitary gland contracted the uterus of a pregnant cat. (The hormone is found unchanged in every mammalian species.) Dale named the unknown substance oxytocin, using the Greek words for "quick" and "birth." As early as 1911, physicians began using the pituitary extract to stimulate childbirth contractions. Dale subsequently found that the same extract facilitates the release of mother's milk. In the early 1950s, American biochemist Vincent du Vigneaud found that oxytocin is made up of nine amino acids, and he identified its amino acid sequence. In 1953 du Vigneaud carried out the synthesis of oxytocin, making it the first polypeptide hormone to be synthesized. (Du Vigneaud received the Nobel Prize for Chemistry in 1955 for his breakthrough.)