RAGE Is Responsible For Absorbing Oxytocin In Breastmilk

Scientists have solved the mystery of how oxytocin in breastmilk crosses the gut to reach the bloodstream of baby mice.

AsianScientist (Oct. 17, 2017) – A protein called RAGE is required to help oxytocin cross the gut and enter the bloodstream. These results, published in Scientific Reports, could lead to oral treatments for conditions affected by oxytocin, such as diabetes and autism.

Oxytocin is a peptide hormone important in interpreting and reading social cues and in establishing good communication with others. It is therefore considered to be indispensable to the development of the social brain.

Although oxytocin is found in breastmilk, it is thought to be unable to pass into the baby’s bloodstream due to the gut barrier. However, oxytocin levels of babies drinking their mother’s milk is elevated, suggesting either that breastfeeding triggers oxytocin production in the babies or that oxytocin in the breastmilk is somehow transported across the gut barrier.

In the present study, an international team of researchers led by Professor Haruhiro Higashida of Kanazawa University have found that oxytocin is transported across the gut barrier by the receptor for advanced glycation end-products (RAGE) in neonatal mice.

They found that baby mice had increased levels of oxytocin in their blood when they were either allowed to breastfeed or given oxytocin orally. When oxytocin was fed to mice lacking RAGE, blood oxytocin levels also increased, but stopped doing so when the mice were four-days-old, coinciding with the timing of the closure of the gut.

Similarly, giving adult mice oxytocin orally or directly through the digestive tract led to an increase in blood oxytocin levels in a RAGE-dependent manner. Subsequent mass spectrometry analysis confirmed that oxytocin was transported into the blood in its intact form.

These findings suggest that oxytocin could freely cross the gut up to three days after birth, but when the gut closed at about four days after birth, only mice with RAGE could take up oxytocin from the digestive tract.

This study demonstrates, for the first time, that RAGE is responsible for absorption of oxytocin from the gut into the blood. The present findings indicate that oxytocin is ingested by a specific molecular mechanism and that oxytocin could be orally administered as a medication and/or nutrient supplement in milk.


The article can be found at: Higashida et al. (2017) Intestinal Transepithelial Permeability of Oxytocin into the Blood is Dependent on the Receptor for Advanced Glycation End Products in Mice.

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Source: Kanazawa University; Photo: Anne Bunner/Flickr/CC.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

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