Mu opioid receptor in the human endometrium: dynamics of its expression and localization during the menstrual cycle

Mu opioid receptor (MOR) mRNA and protein levels in the human endometrium change during the menstrual cycle, showing the highest levels in the late-proliferative phase. These findings suggest a role forMORin reproduction.

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Volume 107, Issue 4, Pages 1070–1077.e1


Lide Totorikaguena, B.S., Estibaliz Olabarrieta, B.S., Roberto Matorras, M.D., Ph.D., Edurne Alonso, Ph.D., Ekaitz Agirregoitia, Ph.D., Naiara Agirregoitia, Ph.D.


The presence of MOR in human endometrium and the dynamic changes during the menstrual cycle suggest a possible role for opioids in reproduction events related to the human endometrium or endometriosis.

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Fertility and Sterility

Editorial Office, American Society for Reproductive Medicine

Fertility and Sterility® is an international journal for obstetricians, gynecologists, reproductive endocrinologists, urologists, basic scientists and others who treat and investigate problems of infertility and human reproductive disorders. 


Go to the profile of Amanda Kallen
over 4 years ago
Very interesting descriptive study regarding the dynamics of mu opioid receptor expression in the endometrium over the menstrual cycle. The function of MOR, and of the dynamic expression pattern changes over the cycle, remains yet unclear, and to my mind it would be informative at this point to delve further into the mechanism regulating these changes in expression, which might give us some clue to functionality. I would be interested to see the effect of trophic hormones, cAMP and/or steroid hormones on expression of the MOR in vitro. An additional question would be whether expression differs in ectopic vs eutopic endometrium. Looking forward to seeing more from these authors!