oxytocin

American  

[ok-si-toh-suhn] / ˌɒk sɪˈtoʊ sən /

noun

1. Biochemistry. a polypeptide hormone, produced by the posterior lobe of the pituitary gland, that stimulates contraction of the smooth muscle of the uterus.

2. Pharmacology. a commercial form of this substance, obtained from beef and hog pituitary glands or especially by synthesis, and used chiefly in obstetrics to induce labor and to control postnatal hemorrhage.

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oxytocin British  

/ ˌɒksɪˈtəʊsɪn /

noun

1. a polypeptide hormone, secreted by the pituitary gland, that stimulates contractions of the uterus or oviduct and ejection of milk in mammals; alphahypophame: used therapeutically for aiding childbirth. Formula: C 43 H 68 N 12 O 12 S 2 Compare vasopressin

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oxytocin Scientific  

/ ŏk′sĭ-tō′sĭn /

1. A polypeptide hormone secreted by the posterior portion of the pituitary gland. Oxytocin stimulates the contraction of smooth muscle of the uterus during childbirth and facilitates ejection of milk from the mammary glands.

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Etymology

Origin of oxytocin

First recorded in 1925–30; oxytoc(ic) + -in ²

Explanation

Oxytocin is a hormone associated with feelings of love and affection — it also aids in childbirth, by stimulating the uterus to start contracting. Oxytocin is most often associated with delivering and nurturing new babies, as it triggers warm, loving, and protective feelings. Nearly everyone experiences the release of oxytocin, even if they don't give birth; its nickname is "the love hormone," and if you've ever had a huge crush on someone, some of your feelings were likely caused by oxytocin! Oxytocin is derived from the Greek oxutokia, or "sudden delivery," a reference to the start of contractions before a baby is born.

Example Sentences

See Examples For:

oxytocin

Several hormones can spike in men when they become dads, including oxytocin, linked to better relationship quality; vasopressin, associated with emotional bonding; and prolactin, which promotes lactation in women and caregiving behavior in guys.

From Los Angeles Times ● Jun. 10, 2026

FDA-approved peptide drugs such as insulin and oxytocin have been available for decades.

From Salon ● Apr. 4, 2026

“When a baby nurses, oxytocin rises, which triggers milk letdown,” she says.

From Slate ● Mar. 15, 2026

Intimacy plus oxytocin outperformed intimacy and placebo, suggesting that oxytocin amplifies the effect of physical affection on healing.

From The Wall Street Journal ● Dec. 4, 2025

But my saving human connection—my oxytocin receptor, as it were—is George, the nineteen-year-old Czech dishwasher who has been in this country exactly one week.

From "Nickel and Dimed: On (Not) Getting By in America" by Barbara Ehrenreich