I. Physiology

  1. Prolactin is synthesized and secreted by Lactotrophs in the anterior pituitary
    1. Stimulation (releasing factors)
      1. Vasoactive intestinal polypeptide (VIP)
      2. Thyroid Releasing Hormone (TRH, short-term factor only)
      3. Estrogen
    2. Inhibition
      1. Hypothalamic Dopamine (Prolactin Inhibiting Factor or PIF)
  2. Prolactin Characteristics
    1. Polypeptide hormone with 198 amino acids
    2. Resembles Human Growth Hormone (hCG)
    3. Resembles Human Placental lactogen (hPL)
  3. Prolactin increases with infant Breast Feeding
    1. Increases with each Breast Feeding episode
    2. Prolactin levels gradually level off after the first few months of regularly Breast Feeding
    3. Prolactin decreases to normal within 1-2 months of stopping Breast Feeding

II. Preparation

  1. Fasting level drawn before noon
  2. No Breast stimulation in last 48 hours

III. Interpretation: Normal Levels

  1. Adult: <20 ng/ml
  2. Newborn: 100 to 300 (falls below 20 after 6 weeks)
  3. Pregnancy
    1. First Trimester: <80 ng/ml
    2. Second trimester: <160 ng/ml
    3. Third Trimester: <400 ng/ml
  4. Lactation
    1. Initially (<3 months postpartum)
      1. First week: 100 ng/ml basal level
      2. First 1-2 months: 50 ng/ml basal level
      3. Suckling raises Prolactin 10-20 fold above basal
    2. Later (3-6 months postpartum)
      1. Basal rates approach non-pregnant levels
      2. Suckling may double basal level
  5. References
    1. Bakerman (1984) ABCs of Lab Data, p. 342

IV. Interpretation: Increased Prolactin > 20 ng/ml

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Ontology: Prolactin (C0033371)

Definition (CHV) milk producing hormone
Definition (CHV) milk producing hormone
Definition (CHV) milk producing hormone
Definition (CHV) milk producing hormone
Definition (CHV) milk producing hormone
Definition (NCI) A hormone that is made by the pituitary gland (a pea-sized organ in the center of the brain). Prolactin causes a woman's breasts to make milk during and after pregnancy, and has many other effects in the body.
Definition (MSH) A lactogenic hormone secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). It is a polypeptide of approximately 23 kD. Besides its major action on lactation, in some species prolactin exerts effects on reproduction, maternal behavior, fat metabolism, immunomodulation and osmoregulation. Prolactin receptors are present in the mammary gland, hypothalamus, liver, ovary, testis, and prostate.
Definition (CSP) glycoprotein hormone secreted by the anterior pituitary; in mammals it stimulates the production of milk and assists in maintaining the corpus luteum.
Definition (NCI) Human prolactin (227 aa, 26 kDa precursor) is encoded by the human prolactin (PIT1) gene. This secreted lactogenic glycoprotein is expressed in both anterior pituitary lactotropes and the decidual endometrium. It acts primarily on the mammary gland and, in synergy with estrogen, induces progesterone release by corpus luteum cells to render the uterine mucosa suitable for implantation.
Concepts Amino Acid, Peptide, or Protein (T116) , Pharmacologic Substance(T121) , Hormone(T125)
MSH D011388
SnomedCT 70454002, 82166002
English Hormone, Pituitary Lactogenic, Hormone, Pituitary Mammotropic, Lactogenic Hormone, Pituitary, Luteotropin, Mammotropic Hormone, Pituitary, Mammotropin, Pituitary Lactogenic Hormone, Pituitary Mammotropic Hormone, Prolactin, luteotropin, LTH (luteotropic hormone), lactogenic hormone, luteotropic hormone, mammary stimulating hormone, Lactogenic hormone, PROLACTIN, Prolactin [Chemical/Ingredient], lth, prolactins, prolactine, prolactin, LTH, PRL (Prolactin), Prl - Prolactin, Prolactin preparation, Prolactin (substance), Prolactin preparation (product), Prolactin preparation (substance), PRL
Swedish Prolaktin
Czech prolaktin
Finnish Prolaktiini
French Lactostimuline, Mammotropine, Mammotrophine, PRL (Prolactin), Hormone galactogène, Prolactine
Italian PRL (Prolattina), Ormone pituitario lattogenico, Mammotropina, Ormone pituitario della mammotropina, Prolattina
Russian LAKTOGENNYI GORMON GIPOFIZA, LIUTEOTROPIN, LAKTIKOTROPNYI GORMON, PROLAKTIN, MAMMOTROPIN, MAMMOTROPNYI GORMON GIPOFIZA, ЛАКТИКОТРОПНЫЙ ГОРМОН, ЛАКТОГЕННЫЙ ГОРМОН ГИПОФИЗА, ЛЮТЕОТРОПИН, МАММОТРОПИН, МАММОТРОПНЫЙ ГОРМОН ГИПОФИЗА, ПРОЛАКТИН
Japanese ラクトトロピン, 乳腺刺激ホルモン-下垂体性, 黄体刺激ホルモン, プロラクチン, ルテオトロピン, 下垂体性乳腺刺激ホルモン, 下垂体性泌乳刺激ホルモン, 乳汁分泌ホルモン, 乳腺刺激ホルモン, 催乳ホルモン, マンモトロピン
Spanish prolactina (producto), preparado de PL, preparado de prolactina (producto), preparado de prolactina, preparado de prolactina (sustancia), prolactina (sustancia), prolactina, Prolactina, Hormona-Lactogeno Pituitaria, Hormona Mamotropica Pituitaria, Hormona Mamotropico-Pituitaria, Mamotropina, Hormona Mamotrópica Pituitaria, Hormona Mamotrópico-Pituitaria, Hormona-Lactógeno Pituitaria
Croatian PROLAKTIN
Polish Prolaktyna, Laktotropina, Hormon laktotropowy
German Mammotropin, Prolactin, Lactogene Hormone, hypophysäre, Mammotrope Hormone, hypophysäre
Portuguese Hormônio Lactogênico Pituitário, Hormônio Mamotrófico Pituitário, Hormônio Mamotrópico Pituitário, Mamotrofina, Mamotropina, Prolactina