prolactin

noun

pro·​lac·​tin prō-ˈlak-tən 

: a protein hormone of the anterior lobe of the pituitary that induces lactation

Examples of prolactin in a Sentence

Recent Examples on the Web

In new mothers, for instance, an increase in the hormone prolactin helps lay the groundwork for breastfeeding. — Joshua Rothman, New Yorker, 19 June 2026

Plus, men don’t have the hormonal surges of prolactin that stimulate milk production in women. — Dr. Jamin Brahmbhatt, CNN Money, 26 Oct. 2025

For those who continue to feed, baseline prolactin decreases (though still rises during feeding), and oxytocin becomes more consistent. — Hannah Silverman, Parents, 16 Feb. 2026

At the same time, higher levels of growth hormone and prolactin, a hormone that helps regulate the immune system and cell growth, enhance immune function and tissue repair, helping skin recover from daily stressors. — Joanna Fong-Isariyawongse, The Conversation, 12 Sep. 2025

Word History

Etymology

pro- entry 2 + lact- + -in entry 1

First Known Use

1932, in the meaning defined above

Rhymes for prolactin

• actin

Medical Definition

prolactin

noun

pro·​lac·​tin prō-ˈlak-tən 

: a protein hormone of the adenohypophysis of the pituitary gland that induces and maintains lactation in the postpartum mammalian female

—abbreviation PRL

called also luteotropic hormone, luteotropin, mammotropin