Dopamine and morphine stimulate nitric oxide release in human endometrial glandular epithelial cells

OBJECTIVE: Previous studies have shown that human endometrial glandular epi thelial cells contain endothelial nitric oxide synthase indicating that the endometrium might produce nitric oxide (NO). We conducted this study to id entify stimuli that can activate a transient NO release from endometrial gl andular epithelial cells because NO is an important intracellular and inter cellular signal transduction pathway in reproductive cycle. METHODS: Endometrial glandular epithelial cells, free of endothelial cells, were isolated from human endometrial specimens and maintained viable in RP MI 1640 medium with 2% fetal bovine serum for 2-4 days. Nitric oxide releas e from the glandular cells in response to stimuli was monitored continuousl y amperometrically. RESULTS: Among the substances examined, we found that dopamine and morphine stimulated a transient surge of NO production that was dose-dependent, whe reas estrogen, progesterone, or relaxin (RLX) had no short-term effect on N O release. Cells treated with RLX or dopamine for 4 days enhanced the dopam ine-induced NO release fourfold to sixfold, with the peak of the NO surge s hifting from 35 to 15 seconds. CONCLUSION: Endometrial glandular cells were capable of producing NO. Dopam ine and morphine were potent stimuli for a transient surge of NO release fr om endometrial glandular cells. Furthermore, prolonged exposure to dopamine or RLX enhanced the sensitivity of NO release in endometrial glands. (J So c Gynecol Investig 2000;7:343-7) Copyright (C) 2000 by the Society for Gyne cologic Investigation.