prolactin

prolactin /pro·lac·tin/ (-lak´tin) a hormone of the anterior pituitary that stimulates and sustains lactation in postpartum mammals, and shows luteotropic activity in certain mammals.

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pro·lac·tin (pr-lktn)

n.

Abbr. PRL A pituitary hormone that stimulates and maintains the secretion of milk. Also called lactogenic hormone, lactotropin, luteotropic hormone, luteotropin.

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Prolactin

A hormone that helps the breast prepare for milk production during pregnancy.

Mentioned in: Pituitary Dwarfism

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prolactin (PRL)

[prōlak′tin]

Etymology: Gk, pro, before, lac, milk

a hormone produced and secreted into the bloodstream by the anterior pituitary gland. Prolactin stimulates the development and growth of the mammary glands after the glands have been prepared by estrogen, progesterone, thyroxine, insulin, growth hormone, glucocorticoids, and human placental lactogen. After parturition, prolactin, together with glucocorticoids, is essential for the initiation and maintenance of milk production. Prolactin synthesis and release from the pituitary are mediated by the central nervous system in response to suckling by the infant. When suckling or its mechanical equivalent ceases, prolactin secretion slows and milk production ceases. Prolactin has no known function in human males. Prolactin is similar to growth hormone in its chemical structure. Prolactin excess is seen with prolactin-secreting pituitary tumors in both sexes. Also called lactogenic hormone.

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prolactin,

n See hormone, lactogenic.

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prolactin

a hormone secreted by the anterior pituitary that promotes the growth of mammary tissue and stimulates and sustains milk production in postpartum mammals, and shows luteotropic activity in certain mammals. Promotes the secretion of milk in the crop of pigeons and doves. Called also lactogenic hormone, luteotropic hormone, LTH and mammotropin. It is identical with luteotropin.

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prolactin inhibitory factor (PIF)

probably the catecholamine dopamine, released in the hypothalamus, carried to the anterior pituitary via the hypophyseal portal system, and inhibits the secretion of prolactin.

prolactin releasing factor (PRF)

appears to be released from the hypothalamus in a pulsatile fashion and it is the fluctuation in PRF that regulates the circulating level of prolactin.