Several isoforms of Nitric Oxide (NO) synthase are present in the rat oviduct

PÉREZ MARTÍNEZ, S.; FRANCHI, A.M.; SUBURO, A.; HERRERO, M.B.; GOIN, J.C.; OHSHIMA, H.; GIMENO, M.F.

BIOCELL

Instituto de Histología y Embriología "Dr. Mario H. Burgos" (IHEM - CONICET)

Lugar: Mendoza; Año: 1997 vol. 21 p. 215 - 223

0327-9545

We have studiesd the possible existence of NO synthase in rat oviducts, using different methodologies. Measurements of the conversion of L-[14C] arginine into L-[14C] citrulline demonstrated the presence of significant NO synthase activity that could be inhibited by N-monomethyl-L-arginine (L-NMMA), N-L-arginine-methyl-ester (L-NAME), aminoguanidine (AG), methylene blue (MB), and EGTA. The inhibition pattern suggested that both Ca2+ dependent (or constitutive) and Ca2+ independent (or inducible) NO synthase isoforms were present in the rat oviduct. This was confirmed by SDS-PAGE and Western blotting of oviductal homogenates, where two different bands could be recognized. A 155 kDa band was detected by a serum against neuronal NO synthase, whereas a 120 kDa was detected by a serum against a macrophage NO synthase. Immunohistochemistry revealed the presence of neuronal NO synthase in a sparse population of nerve fibers mainly confined to the medial third of the oviduct. Epithelial cells contained the largest deposit of immunoreactivity. All antisera, whether directed to neuronal or inducible NO synthases, gave a strong reaction in subpopulations of epithelial cells, usually appearing in clusters. These cells also exhibited a strong NADPH diaphorase activity and were much more numerous towards the fimbrial end of the tube.