Nitric oxide synthesis is increased in the endometrial tissue of women with endometriosis.
BACKGROUND
Previous studies have shown that peritoneal macrophages from women with endometriosis produce excess nitric oxide (NO). This study was designed to quantify the amount of NO and determine the expression of endothelial (eNOS) and inducible NO synthases (iNOS) in women with and without endometriosis.


METHODS
An enzyme-linked immunosorbent assay (ELISA) was performed on endometrial tissues obtained from controls (myoma, n = 30) and on eutopic/ectopic endometrial tissues from endometriosis patients (n = 34) to evaluate eNOS and iNOS protein concentrations in these endometrial tissues. A rapid-response chemiluminescence analyser was used to measure NO directly in fresh endometrial tissues.


RESULTS
Mean (+/- SEM) levels of NO were significantly increased in the endometrial tissues of women with endometriosis (13.2 +/- 7.8 versus 19.8 +/- 12.6 nmol/g tissue; P = 0.016). Apparently higher levels of NO were found in ectopic compared with eutopic endometrium (P = 0.057). Endometrial tissues of women with endometriosis appeared to contain more iNOS than those of controls (3.6 +/- 2.2 versus 8.6 +/- 12.2 pg/ microg protein; P = 0.06), but no significant difference was found in eNOS levels.


CONCLUSIONS
Greater amounts of NO and NOS are present in the endometrial tissues of women with endometriosis, implying a possible role for NO in the pathogenesis of endometriosis.
Wu
Ming-Yih
MY
Department of Obstetrics and Gynecology, College of Medicine and the Hospital, National Taiwan University, Taipei, Taiwan.
Chao
Kuang-Han
KH
Yang
Jehn-Hsiahn
JH
Lee
Tsung-Hsien
TH
Yang
Yu-Shih
YS
Ho
Hong-Nerng
HN
D004715:Endometriosis / Q000201:enzymology / Q000378:metabolism*; D004717:Endometrium / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008163:Luminescent Measurements; D009566:Nitrates / Q000032:analysis; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000032:analysis / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III; D009573:Nitrites / Q000032:analysis
D009566:Nitrates; D009573:Nitrites; D009569:Nitric Oxide; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III