Changes in Endogenous Oxytocin Levels and the Effects of Exogenous Oxytocin Administration on Body Weight Changes and Food Intake in Polycystic Ovary Syndrome Model Rats

Abstract

Polycystic ovary syndrome (PCOS) is frequently seen in females of reproductive age and is associated with metabolic disorders that are exacerbated by obesity. Although body weight reduction programs via diet and lifestyle changes are recommended for modifying reproductive and metabolic phenotypes, the drop-out rate is high. Thus, an efficacious, safe, and continuable treatment method is needed. Recent studies have shown that oxytocin (OT) reduces body weight gain and food intake, and promotes lipolysis in some mammals, including humans (especially obese individuals), without any adverse effects. In the present study, we evaluated the changes in endogenous OT levels, and the effects of acute and chronic OT administration on body weight changes, food intake, and fat mass using novel dihydrotestosterone-induced PCOS model rats. We found that the serum OT level was lower in PCOS model rats than in control rats, whereas the hypothalamic OT mRNA expression level did not differ between them. Acute intraperitoneal administration of OT during the dark phase reduced the body weight gain and food intake in PCOS model rats, but these effects were not observed in control rats. In contrast, chronic administration of OT decreased the food intake in both the PCOS model rats and control rats. These findings indicate that OT may be a candidate medicine that is efficacious, safe, and continuable for treating obese PCOS patients.

The Role of Oxytocin in Polycystic Ovary Syndrome: A Systematic Review

“…Previous findings indicated that OT administration significantly reduced the area of adipocytes, the serum triglyceride, aspartate aminotransferase level alanine aminotransferase, and alkaline phosphatase in ovariectomized rats [67]. Moreover, according to the results reported by Yamamoto and colleagues [63], an OT-mediated mechanism was involved in obesity and food intake in the PCOS rats. However, in PCOS the authors found a decrease in serum OT levels and no difference in the hypothalamic mRNA expression of OT and OXTR after the acute systemic administration of OT.…”

Age-Dependent Changes in the Effects of Androgens on Female Metabolic and Body Weight Regulation Systems in Humans and Laboratory Animals

“…In addition to well-established roles in the regulation of labor and lactation in female mammals [65], recent studies have shown that OT also has behavioral, psychological, and physiological functions, including metabolism, appetite, and body weight regulation [13,66,67]. In a previous study, we showed that serum OT levels were decreased in long-term DHT-administered PCOS model rats and that supplementation of OT attenuated food intake and body weight in these animals, indicating that OT might be related to the effects of androgens on appetite and body weight regulation [68]. Interestingly, the effects of estrogens on OT are completely the opposite of those of androgens.…”

Dual Oxytocin Receptor-G Protein Signaling in the Autoregulation of Activities of Oxytocin Neurons

“…In addition, Rett syndrome, characterized by dysfunction in neuronal excitation/ inhibition balance, potentially due to deficits in K + / Cl − cotransporter 2, is associated with deficits in an insulin-like growth factor-1 and OT signaling crosstalk during postnatal development; that can be improved by OT administration [176]. Interestingly, OT may be used for the treatment of women who have polycystic ovary syndrome, primary ovarian insufficiency, and uterine fibroids that often cause infertility [177,178]. In women with severe preeclampsia, an intravenous bolus of 5 IU OT following delivery can increase heart rate, decrease systemic vascular resistance, and reduce blood pressure, and thus improve disease severity [179].…”