Human placental lactogen

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chorionic somatomammotropin hormone 1 (human placental lactogen)
Chr. 17 q22-q24
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chorionic somatomammotropin hormone 2
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Chr. 17 q22-q24
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Human placental lactogen (hPL), also called human chorionic somatomammotropin (hCS) or human chorionic somatotropin, is a

human growth hormone, hPL is encoded by genes on chromosome 17q22-24. It was identified in 1963.[2]

Structure

hPL

X-ray diffraction to a resolution of 2.0 Å.[1]

Levels

hPL is present only during pregnancy, with maternal serum levels rising in relation to the growth of the fetus and placenta. Maximum levels are reached near term, typically to 5–7 mg/L.

multiple gestation. Little hPL enters the fetal circulation. Its biological half-life is 15 minutes. Some women with higher BMI show lower levels of placental lactogen, but whether prenatal health behaviors influence hPL levels or if hPL influences infant birth weight is uncertain.[4]

Physiologic function

hPL affects the metabolic system of the maternal organism in the following manners:

  • In a bioassay, hPL mimics the action of prolactin, yet it is unclear whether hPL has any role in human lactation.
  • Metabolic:
    • ↓ maternal
      blood glucose levels
      .
    • ↓ maternal glucose utilization, which helps ensure adequate fetal nutrition (the mother responds by increasing beta cells). Chronic hypoglycemia leads to a rise in hPL.
    • ↑
      free fatty acids. With fasting and release of hPL, free fatty acids become available for the mother as free fatty acids do not cross the placenta, so that relatively more glucose can be utilized by the fetus. With sustained fasting, maternal ketones formed from free fatty acids can cross the placenta
      and be used by the fetus.

These functions help support fetal nutrition even in the case of maternal malnutrition.

hPL is a potent agonist of the prolactin receptor and a weak agonist of the growth hormone receptor.[5]

Prolactin-like activity

hPL has been found to bind to the prolactin receptor with equal

mammogenesis during this time.[6] However, the relative affinities of hPL and prolactin for the human prolactin receptor have yet to be published and the effects of hPL on normal human mammary epithelial tissue have not yet been investigated, and so a definitive role of hPL in human mammary gland development during pregnancy has not been established at present.[6]

Growth hormone-like activity

hPL has weak actions, similar to those of growth hormone, causing the formation of protein tissues in the same way that growth hormone, but 100 times more hPL than growth hormone is required to promote growth.[7] However, hPL has a blood level of more than 50 times that of hGH,[8] hence its effects must not be ignored. An enhancer for the human placental lactogen gene is found 2 kb downstream of the gene and participates in the cell-specific control gene expression.[citation needed]

Clinical measurement

While hPL has been used as an indicator of fetal well-being and growth, other

fetal testing methods have been found to be more reliable.[citation needed] Also, normal pregnancies have been reported with undetectable maternal levels of hPL.[citation needed
]

See also

References

  1. ^
    PMID 16546209
    .
  2. PMID 14068826
    .
  3. PMID 10841628
    . Retrieved 2018-03-23.
  4. PMID 36157466
    .
  5. ISBN 978-0-323-32195-2
    .
  6. ^
    ISBN 978-1-4613-3688-4
    .
  7. ISBN 81-8147-920-3. This hormone has weak actions similar to those of growth hormone, causing the formation of protein tissues
    in the same way that growth hormone.
  8. ^ "Growth Hormone: Reference Range, Interpretation, Collection and Panels". 2016-06-01. {{cite journal}}: Cite journal requires |journal= (help)

Further reading

  • Speroff L, Glass RH, Kase NG (1999). Clinical gynecologic endocrinology and infertility (Sixth ed.). Hagerstwon, MD: Lippincott Williams & Wilkins.
    ISBN 0-683-30379-1
    .

External links
Retrieved from "https://en.wikipedia.org/w/index.php?title=Human_placental_lactogen&oldid=1177641562"