Tognetti T, Estevez A, Luchetti C G, Sander V, Franchi A M, Motta A B
Laboratorio de Fisiopatologi;a Ovárica, Centro de Estudios Farmacológicos y Botánicos (CEFYBO): Consejo Nacional de Investigaciones Cienti;ficas y Técnicas (CONICET), Serrano 669, (C1414DEM), Buenos Aires, Argentina.
Prostaglandins Leukot Essent Fatty Acids. 2003 Nov;69(5):359-64. doi: 10.1016/j.plefa.2003.07.002.
The present study was designed to investigate the relationship between the nitric oxide (NO) system and endothelin 1 (ET-1) in the mechanism of corpus luteum (CL) development and consequently regression in rats. We first evaluated basal ET-1 levels in ovarian tissue from rats with different stages of CL development. An increased ovarian ET-1 content was found during CL regression. In a dose-department response, ET-1 decreased progesterone (P4) and increased prostaglandin (PG) PGF2alpha production. By means of a competitive nitric oxide synthase (NOS) inhibitor: L-nitro arginine methyl ester (L-NAME) and a slow NO releasing: diethyl-aminetriamine (DETA-NONOate), we demonstrated that NO system could be the intermediary in the ET-1 diminishing P4 production. The Western blot analysis revealed an increase on iNOS while eNOS protein expression was diminished. We also found a diminution of total NOS activity after ET-1 treatment. These data suggest the existence of a functional relationship between ET-1 and NOS isoforms leading the regulation of CL functionally.
