Photo credit: Chaps1 (CC BY 2.0)

Why does skin color change during pregnancy?

The link between hormonal changes and changes in skin pigment during pregnancy are starting to be revealed.

Factors controlling pigment production in skin are complex and poorly understood. Cells called melanocytes produce a pigment called melanin, which makes the skin darker. It has been known for a long time that skin color often changes during pregnancy, which suggests that sex hormones may be involved. However, the specific hormones and signaling mechanisms responsible for the changes have remained largely undefined.

Estrogen and progesterone are two of the main female sex hormones. Christopher Natale and colleagues now show that estrogen increases pigment production in human melanocytes, and progesterone decreases it.

For hormones to signal to cells, they must bind to and activate particular receptor proteins. Further investigation by Natale and colleagues revealed that estrogen and progesterone regulate pigment production by binding to receptors that belong to a family called G protein-coupled receptors. These receptors can signal rapidly once activated by sex hormones, and may serve as therapeutic targets for treating pigmentation disorders.

Skin diseases that cause inflammation often also cause changes in skin color. Natale and colleagues noticed several other G protein-coupled receptors that are likely to control pigmentation through similar mechanisms. Future analyses of the roles that these other receptors perform in melanocytes may therefore reveal how inflammation-based pigmentation changes occur.

To find out more

Read the eLife research paper on which this eLife digest is based: “Sex steroids regulate skin pigmentation through nonclassical membrane-bound receptors” (April 26, 2016).
eLife is an open-access journal that publishes outstanding research in the life sciences and biomedicine.
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