Asymmetric dimethylarginine (ADMA), nitric oxide metabolite, and estradiol levels in serum and peritoneal fluid in women with endometriosis

BACKGROUND: Increase in nitric oxide (NO) concentration accompanied by alteration in peritoneal immune defense reactions is involved in the pathogenesis of endometriosis. Asymmetric dimethylarginine is an endogenous competitive inhibitor of NO synthase. This study was designed to compare NO metabolite (nitrite), asymmetric dimethylarginine, and estradiol concentrations in serum and peritoneal fluid (PF) of patients with and without endometriosis. MATERIALS AND METHODS: Subjects were assigned to two groups based on their laparoscopic results. The groups consisted of women with and without endometriosis (90 and 89 participants, respectively). The serum and peritoneal levels of nitrite (stable NO metabolite), asymmetric dimethylarginine, and estradiol were measured using enzyme-linked immunosorbent assay (ELISA) kits. These parameters were analyzed and compared between the groups statistically using SPSS software version 16. RESULTS: Both nitrite and asymmetric dimethylarginine levels were significantly higher in the serum of the participants from both groups than those in the PF group (P < 0.05). However, no significant difference in the asymmetric dimethylarginine level was detected between the two groups. In addition, the PF level of nitrite increased significantly in patients with endometriosis when compared with non-endometriosis subjects (P < 0.05). The PF levels of estradiol in both groups were significantly higher than the serum levels of estradiol (P < 0.05). CONCLUSIONS: The NO metabolite level of PF implies the possible role of NO in the pathogenesis of endometriosis.