Abstract
OBJECTIVES: The purpose of this study was to investigate the change in plasma anandamide (AEA) levels throughout the normal menstrual cycle, and to analyze the relationship among AEA, sex steroids and gonadotrophins. MATERIALS AND METHODS: The patients were fertile women with normal menstrual cycle, proposed to get in vitro fertilization (IVF) treatment due to oviduct obstruction or male infertility. Patients were divided into two groups, cross-sectional (n=79) and longitudinal (n=10). The plasma AEA levels were examined by the ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) system. The serum levels of follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), and progesterone (P) were measured by chemiluminescence. RESULTS: The AEA levels in the late follicular phase were slightly higher than those in the early follicular phase. Subsequently, the AEA levels peaked at the time of ovulation in both two cohorts. Finally, the lowest AEA levels were measured in the luteal phase. Moreover, there were highly significant positive correlations between the plasma AEA concentration and the serum levels of FSH, LH and E2, whereas the AEA level was not correlated with P during the normal menstrual cycle. CONCLUSION: Our observations reveal a dynamic change in the plasma AEA level, which is closely associated with the levels of gonadotrophin and sex steroid hormones, suggesting that the hormones may be involved in the regulation of AEA levels during the menstrual cycle. Our studies help to design new strategies to improve implantation and treatments for reproductive diseases.