Relationship between Endothelin- 1 and Nitric Oxide System in the Corpus Luteum Regression”

TOGNETTI T; ESTEVEZ A; LUCHETTI CG; SANDER V; FRANCHI AM; MOTTA AB

PROSTAGLANDINS LEUKOTRIENES AND ESSENTIAL FATTY ACIDS

Elsevier

Lugar: Amsterdam; Año: 2003 vol. 69 p. 359 - 364

0952-3278

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.