HOME HELP CONTACT US SUBSCRIPTIONS ARCHIVE SEARCH		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Accepted manuscript (PDF) All Versions of this Article: JOE-07-0509v1 199/2/307    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Tripathi, V. Articles by Krishna, A. Search for Related Content PubMed PubMed Citation Articles by Tripathi, V. Articles by Krishna, A.

V Tripathi, Department of Animal Science, M.J.P. Rohilkhand University, Bareilly, 243 006, India
A Krishna, Zoology, Banaras Hindu University, Varanasi, India

Correspondence: Vrajesh Tripathi, Email: vrajeshtripathy{at}yahoo.co.in

Abstract

The purpose of the study was to demonstrate the presence of nitric oxide synthase (NOS) isoforms (nNOS, iNOS and eNOS) and role of nitric oxide (NO) in the ovary of Heteropneustes fossilis. In one half of the ovary collected during different reproductive stages, NOS isoforms were localized immunohistochemically in paraffin sections whereas the other half was processed for NOS and NO quantification using western blot followed by densitometry and nitrate/nitrite assay respectively. The role of NO on oocyte maturation was studied by examining the effect of NO-donor (sodium nitroprusside; SNP) and NOS-inhibitor (N-nitro-L-arginine methyl ester; L-NAME) on 17,20β-dihydroxy-4-pregnen-3-one (17,20β-P) induced germinal vesicle breakdown (GVBD) in the cultured oocyte collected during pre-spawning phase. NOS immunostaining was predominantly localized in previtellogenic follicles, with nNOS detected in nucleus and cytoplasm of oocytes whereas iNOS and eNOS localized in granulosa, theca cells and cytoplasm of oocytes. The NOS expression was higher in previtellogenic phase as compared to vitellogenic phase. The nitrate/nitrite concentrations in ovary showed gradual increase from recrudescence (4.9±0.19 nM/mg protein) to late previtellogenic phase (7.02±0.53 nM/mg protein), but showed a sharp decline during the vitellogenic phase (0.41±0.053 nM/mg protein). Serum and ovarian nitrate/nitrite level showed a close association during reproductive cycle. The results showed increase in NOS activity and nitrate/nitrite concentrations as the follicle grow suggesting involvement of NO in follicular development. SNP significantly inhibited 17,20β-P induced GVBD in fish oocytes. Thus it is concluded that the fish ovary possesses NOS/NO system and a possibility that NO has a role in follicular development and regulation of oocyte maturation in fish, H. fossilis.