AJP - Endocrinology and Metabolism, Vol 270, Issue 3 E471-E476, Copyright © 1996 by American Physiological Society
Interaction between nitric oxide and prostaglandin E2 pathways in pregnant rat uteri
Y. L. Dong and C. Yallampalli
Department of Obstetrics and Gynecology, The University of Texas Medical Branch, Galveston 77555, USA.
We examined the possible interrelationship between nitric oxide (NO) and
cyclooxygenase (COX) products in the uterus during pregnancy and labor.
Results indicate that 1) rat uteri during labor, at term, demonstrated a
69% decrease in nitrite production and a 217% increase in prostaglandin E2
(PGE2) production compared with day 18 of pregnancy; 2) interleukin-1 beta
(IL-1 beta) induced a pronounced elevation of both nitrites and PGE2 in rat
uteri; 3) diethylenetriamine/NO, a donor of NO, induced a significant
increase of PGE2 production by the uterus in a dose-dependent manner; 4)
NG-nitro-L-arginine methyl ester, an inhibitor of NO synthesis, markedly
inhibited IL-1 beta-induced nitrite and PGE2 in rat uteri; this inhibitory
action was reversed by coincubation with L-arginine; 5)exogenous PGE2
significantly inhibited IL-1 beta-induced, but not constitutive, nitrite
production; and 6) inhibition of endogenous PGE2 by indomethacin
substantially increased IL-1 beta-induced nitrite production. Thus the
interaction between NO and COX pathways might be important in the
regulation of uterine contractility during pregnancy and labor.
