Distribution of NADPH-diaphorase and Nitric Oxide Synthase (NOS) in Different Regions of Porcine Oviduct During the Estrous Cycle

Abstract

S U M M A R YNitric oxide synthase (NOS) is responsible for the biological production of nitric oxide (NO) in several organs, including those of the reproductive tract. We investigated potential changes in NADPH-diaphorase (NADPH-d) activity (marker for NOS activity) and the presence and distribution of NOS in the porcine oviduct. Tissues were obtained from gilts ( n ϭ 16) on different days of the estrous cycle. One fallopian tube was used for histoand immunohistochemistry and the other for Western blotting analysis. NADPH-d activity was much higher in the epithelium of the mucosa than in the myosalpinx. The highest activity of NADPH-d was always found in the epithelium of the isthmus. The intensity of the reaction (arbitrary units Ϯ SEM) in isthmus epithelium increased from the postovulatory period until early proestrus (96.2 Ϯ 11.2) and then gradually decreased. The lowest intensity of NADPH-d reaction in the epithelium of the isthmus was seen at estrus (58.4 Ϯ 7.7). The most intense NADPH-d activity in myosalpinx of all parts of the oviduct was observed at the postovulatory stage of the estrous cycle (isthmus 38.3 Ϯ 2.5; ampulla 35.6 Ϯ 4.2; infundibulum 24.7 Ϯ 0.8) and then decreased during the remaining stages of the estrous cycle ( p Ͻ 0.001). The presence of endothelial NOS (eNOS) was detected in epithelial cells of mucosa and in endothelium of vascular tissues and myosalpinx during all studied days of the estrous cycle. The positive reaction for inducible NOS (iNOS) was restricted only to the endothelium of lymph vessels and some blood vessels. Because our Western blotting analysis revealed that porcine oviduct contains eNOS but not iNOS, we suggest that eNOS is the main isoform of NOS expressed in the porcine oviduct. We concluded that the different activity of NADPH-d in the various regions of the oviduct, accompanied by changes in its activity during the course of the estrous cycle, could indicate an important role of NO in regulation of tubal function.

Region-specific expression of nitric oxide synthases in the bovine oviduct during the oestrous cycle and in vitro

“…In agreement with our mRNA data for iNOS, the lowest expression of NADPH diaphorase as a marker for NOS was found in the isthmus at oestrus (Gawronska et al 2000). High expression was noticed during the luteal phase (Gawronska et al 2000).…”

“…NADPH diaphorase was demontrated mainly in the oviduct epithelium of man, rat and pig (Bryant et al 1995, Ekerhovd et al 1999, Gawronska et al 2000, and eNOS protein was consistently present in oviduct epithelial cells of different species (Bryant et al 1995, Rosselli et al 1996, Ekerhovd et al 1997, Gawronska et al 2000. In the present study, we clearly demonstrate the presence of both eNOS and iNOS in BOEC.…”

“…High expression was noticed during the luteal phase (Gawronska et al 2000). The presence of NADPH diaphorase activity in the porcine oviduct has been demonstrated during the oestrous cycle.…”

“…Nevertheless, more comprehensive analyses could help to bridge lack of congruency for different species (Chatterjee et al 1996, Gawronska et al 2000 with respect to cellular localisation, regions of the oviduct and cycle-dependent regulation. Therefore, the present study investigated thoroughly the expression and localisation of iNOS and eNOS in the bovine oviduct of days 0, 3·5, 12 and 18 of the oestrous cycle.…”

Changes in nitric oxide synthase expression in young and adult rats after spinal cord injury

“…In our study, fixation with 4% paraformaldehyde was carried out for 24 h. When fixation with 4% paraformaldehyde is relatively brief (6 h), some NOS immunoreactivity is still evident. 25,26 Therefore, the absence of NADPH-d immunoreactivity for eNOS in our study was likely attributable to the relatively long fixation time.…”