Together these data indicate a putative role of opioids, especially beta endorphin, in reproductive function of women, both centrally and in the periphery (i.e. More recently, the expression of opioid receptors on human oocytes, as well as follicular granulosa cells has been confirmed. In postmenopausal women, no beta endorphin was detectable in follicular fluid (FF). first reported that beta endorphin in human follicular fluid showed higher concentrations in the follicular phase of the menstrual cycle and lower concentrations in the luteal phase. Interestingly, the presence of sex steroids seems to be critical for beta endorphin action in the human pancreas.
Beta endorphin has been shown to modulate pancreatic insulin and glucagon release. While the role of endogenous opioids in the neuroendocrine regulation of the menstrual cycle has been well established, very little is known about the effects of these molecules in the periphery. Although all opioid peptides can bind to each receptor subclass, their affinity for the different receptors vary. Three main opioid receptor classes have been described: µ, κ and δ. Preopiomelanocortin (POMC), preprodynorphine and preproenkephaline are post-translationally processed and function as precursor molecules for the different opioid peptides. The role of endogenous opioids, especially the POMC-derivate beta endorphin, in PCOS has been a research topic for some time, but has not been extensively studied.Īll endogenous opioids share the same n-terminal aminoacid pentasequence, the so-called “opioid motif”. reported about a primary dysfunction of ovarian steroidhormone synthesis in PCOS women. Decades ago, neuroendocrine abnormalities were thought to play a causative role. Many hypotheses regarding the pathogenesis of the disorder have been postulated. The polycystic ovary syndrome (PCOS) is one of the most common endocrinopathies of women in reproductive age. However, together with sex hormones, beta endorphin might play a key role in oocyte maturation. Conclusionīeta Endorphin concentrations in serum and FF do not differ between PCOS- and non PCOS-women undergoing IVF.
In women with biochemical hyperandrogenemia, beta endorphin levels in FF correlated with testosterone levels.
We found a significant correlation between the number of mature Metaphase II (MII) oocytes retrieved and beta endorphin concentration in FF. The concentration of the peptide was higher in serum than in FF, likely due to collection of FF after ovulation induction and corresponding to the early luteal phase. There was no difference in beta endorphin levels between PCOS- and non-PCOS women. Additionally, testosterone was measured before starting the stimulation protocol. Beta endorphin concentrations in serum and follicular fluid, serum levels of insulin, glucose, LH, estradiol and progesterone were measured. Follicular fluid was collected during oocyte retrieval and peripheral blood sampling was performed on the same day. The remaining 43 women served as controls. Sixteen were stratified to the PCOS group using the Rotterdam criteria. Methodsįifty-nine women undergoing in vitro fertilization (IVF) were included in the study. Secondarily, to investigate associations between beta endorphin and other parameters. To compare the concentrations of beta endorphin in serum and follicular fluid (FF) of PCOS- and non-PCOS women.
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