Nitric oxide mediates human chorionic gonadotrophin-induced prostaglandin E generation in rat oocyte-cumulus...

To determine whether nitric oxide (NO) generation mediates human chorionic gonadotrophin (hCG)-induced prostaglandin E (PGE) secretion by oocyte-cumulus complexes (OCC), the secretion of PGE by cultured rat OCC in the presence of NO donors and NO synthase (NOS) inhibitors was characterized. NO donors (sodium nitroprusside and 3-morpholino-sydnonimine-hydrochloride) increased PGE accumulation in OCC to values similar to those obtained in the presence of hCG. The three NOS inhibitors tested (NG-nitro-L-arginine methyl ester, NG-monomethyl-L-arginine and aminoguanidine) prevented the hCG-induced PGE accumulation in cultured OCC. This effect appears to be specific since D-enantiomers NG-nitro-D-arginine methyl ester and NG-monomethyl-D-arginine had no effect. The present results suggest that NO mediates the hCG-induced accumulation of PGE in rat OCC, a process which may occur in vivo in preovulatory follicles prior to ovulation.