Regulation of prostaglandin production by nitric oxide in rat smooth muscle myometrial cells

Smooth muscle myometrial cells isolated by an enzymatic method from estroge nized rats were used after 7-10 days of culture. They were incubated for 24 h with two distinct competitive nitric oxide (NO) inhibitors: NG-monomethy l-l-arginine (L-NMMA: 300 mu M) and L-nitro-arginine methylester (L-NAME: 6 00 mu M, 5 mM and 10 mM). Afterwards, the supernatants were separated in or der to measure nitrite production and prostaglandin PGE synthesis. In the p resent report, we demonstrate that myometrial cells from estrogenized rats are able to produce NO, since all the inhibitors significantly decrease the production of nitrites in the culture media. Furthermore, we report that b oth inhibitors inhibited PGE synthesis by myometrial cells. We also used a donor of NO in the incubation medium for 24 h, sodium nitroprusside (NP), o btaining an strong (P < 0.001) increase in both nitrite and PGE production. We conclude that myometrial cells can produce NO and that one possible rol e of the NO synthetized by this cells may be the modulation of PGE producti on.