Several isoforms of nitric oxide (NO) synthase are present in rat oviduct

PÉREZ MARTÍNEZ S; FANCHI AM; SUBURO AM; HERRERO MB; GOIN JB; OSHIMA H; GIMENO M

BIOCELL

IHEM

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

0327-9545

ABSTRACT: We have studied the possible existence of NO synthase in rat oviducts, using differents methodologies. Measurement of the conversion of L-[14C]arginine into L-[14C]citrulline demonstrated the presence of a significant NO synthase activity that could be inhibited by N-monomethyl-L-arginine (LNMMA),N-L-arginine-methyl-ester (L-NAME). aminoguanidine (AG), methylene blue (ME) and EGTA. The inhibition pattern suggestedthat both Ca2+ dependent (or constitutive) and Ca2+ independent (or inducible) NO synthase isoforms were present in the rat oviduct. This was confim1ed 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 macrophage NO synthase. Immunohistochemistry revealed the presence ofneuronal NO synthase in a sparse population of nerves fibers mainly confined to the medial third of the oviduct. Epithelial cells contained the largest deposits of immunoreactivity. All antisera, whether directed to neuronal or inducible NO synthases, gave a strong reaction in subpopulation 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.