In a recent systematic review published in Current Topics in Molecular Biology, researchers from Portugal reviewed and discussed the role of oxytocin (OT) in polycystic ovary syndrome (PCOS), its association with PCOS symptoms, and the effect of OT administration.
They found that PCOS is associated with decreased serum OT levels, and changes in OT levels are associated with fertility problems and body weight, suggesting a possible role of OT dysfunction in the development of PCOS.
Study: The role of oxytocin in polycystic ovary syndrome: a systematic review. Image credit: MMD Creative/Shutterstock.com
Record
PCOS is a complex and widespread endocrine disorder in women of reproductive age that affects their quality of life. It is characterized by polycystic ovaries, androgen excess and ovulatory dysfunction, often leading to infertility and various metabolic, reproductive and psychological problems.
PCOS is associated with high androgen levels and abnormal LH/FSH (luteinizing hormone/follicle stimulating hormone) ratios, contributing to anovulatory infertility and increased risks during pregnancy.
Biochemically, OT is a nine-amino acid peptide involved in cognitive, emotional, and reproductive functions. While it is produced in the hypothalamus and secreted by the posterior pituitary gland, OT receptors (OXTR) are found in various parts of the body, including the ovaries and prostate.
OT is crucial for various reproductive and behavioral functions in humans, including pregnancy, parturition, lactation, bonding, prosocial behavior, decision making, physical activity, and orgasm.
Previous studies suggest that OT levels are lower in women with PCOS, potentially affecting mood and weight. Animal studies show that OT deficiency can potentially lead to obesity, and OT administration can reduce weight and enhance muscle tone.
Despite these findings, the exact role of OT in SPO remains unclear. In the present systematic review, researchers aimed to clarify the role of OT in PCOS by reviewing all relevant animal and human studies.
Specifically, it focused on (i) identifying potential changes in baseline plasma OT levels in PCOS, (ii) understanding how changes in OT levels may relate to PCOS symptoms, and (iii) investigating the effects of of granting OT in the SPO.
About the study
Databases including PubMed, Scopus and Web of Science were thoroughly searched to identify relevant studies. The review included eight studies, including experimental studies, randomized clinical trials, clinical pilot studies, case-control studies and population genetic studies.
Five of the included studies were conducted in humans (n = 609 women), while three were in animals. He excluded studies of other endocrine diseases, studies of men, reviews and meta-analyses.
Results and discussion
Cohen’s kappa value was found to be 0.742, indicating significant agreement between the two individual reviewers. Human studies have mainly investigated the relationship between OT administration and fertility.
Two clinical trials found that intranasal OT did not improve fertility in PCOS patients, possibly due to inadequate dosing or administration methods.
These studies did not measure OT levels in blood or saliva. One study found lower OT levels in PCOS patients compared to non-PCOS controls and linked these lower levels to hormonal imbalances in the hypothalamic-pituitary-ovarian (HPO) axis.
A case-control study also associated higher OT levels with improved pregnancy rates in women with PCOS. A genetic study examined gene polymorphisms in OXTR in PCOS patients and found five variants associated with PCOS, suggesting a genetic influence on OXTR expression.
Animal studies used rat models to evaluate the effects of OT on metabolic disorders and uterine function. One study found that OT administration regulated uterine contractions in PCOS rats, while another reported that acute OT administration could reduce body weight and food intake in PCOS rats.
Chronic administration of OT was found to reduce food intake and body weight in both PCOS and control rats. Another study found that OT administration reduced body weight, visceral fat, and adipocyte size in a dihydrotestosterone (DHT)-induced PCOS rat model.
Taken together, these findings suggest that OT may affect metabolic and reproductive functions in PCOS, but further research is needed to understand its therapeutic potential.
Furthermore, the review highlighted gaps in current research in the field, such as the need for studies evaluating the impact of OT on prosocial behavior, couple relationships, and sexual satisfaction in PCOS.
Different dosage regimens and administration regimens of OT were also found to be understudied, highlighting the need for further research.
conclusion
In conclusion, the present review thoroughly examined the studies investigating the effect of OT levels or OT administration in PCOS. Most studies highlighted the role of OT in fertility issues, with only one study linking higher OT levels to increased pregnancy rates.
Consistently, basal OT levels were found to be reduced in women with PCOS, suggesting that low OT, along with low FSH levels, contributes to anovulation in PCOS.
In addition, potential molecular mechanisms involving altered OXTRs and genetic variants in PCOS were discussed. These insights are crucial for the potential development of targeted therapies and improving the quality of life of women with PCOS in the future.
