title: Alterations in nitrate/nitrite and nitric oxide synthase in preovulatory follicles in gonadotropin-primed immature rat.
abstract: Nitric oxide synthase (NOS) and nitric oxide (NO) play important roles in ovulation. The purpose of this study was to investigate the changes of intrafollicular nitrate/nitrite concentration and NOS mRNA expression in preovulatory follicles during equine CG (eCG) and human CG (hCG) induced ovulation in immature rats. Immature Sprague-Dawley rats received 15 IU eCG and then 15 IU hCG 48 h later. Rats were killed immediately before, 5 h after or 10 h after hCG injection, and their preovulatory follicles were dissected. Follicular fluid, granulosa cell, and theca cell layers were collected from preovulatory follicles and assayed for NO or NOS mRNA or for in vitro incubation study. Nitrate/nitrite concentration in the follicular fluid decreased significantly 5 and 10 h after hCG injection. Inducible NOS (iNOS) mRNA expression, which was greater in granulosa cell than in the theca cell layer, decreased significantly 5 and 10 h after hCG injection. However, endothelial NOS (eNOS) mRNA expression was detected mainly in the theca cell layer and further increased 5 and 10 h after hCG injection but remained low in granulosa cells. In vitro treatment of granulosa cells with 10(-4) or 5x10(-4) M S-nitroso-L-acetyl penicillamine (NO donor) decreased progesterone production and increased DNA fragmentation. We concluded that the decrease in nitrate/nitrite concentration in preovulatory follicles after hCG injection was due mainly to decreased iNOS expression in granulosa cells. These changes in nitrate/nitrite concentration may prevent apoptosis in preovulatory follicles.
authors.affiliation: Reproductive, Pediatric and Infectious Science, Yamaguchi University School of Medicine, Ube, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Yamagata
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Norihiro
authors.initials: N
authors.lastname: Sugino
authors.forename: Ayako
authors.initials: A
authors.lastname: Harada
authors.forename: Hisako
authors.initials: H
authors.lastname: Takayama
authors.forename: Shiro
authors.initials: S
authors.lastname: Kashida
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kato
mesh_terms: D000818:Animals; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D053938:DNA Fragmentation / Q000187:drug effects; D004958:Estradiol / Q000378:metabolism; D005260:Female; D015571:Follicular Fluid / Q000737:chemistry; D015971:Gene Expression Regulation, Enzymologic; D006107:Granulosa Cells / Q000201:enzymology; D009566:Nitrates / Q000032:analysis / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D009573:Nitrites / Q000032:analysis / Q000378:metabolism*; D006080:Ovarian Follicle / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D010062:Ovulation Induction; D010396:Penicillamine / Q000031:analogs & derivatives* / Q000494:pharmacology; D011374:Progesterone / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013739:Testosterone / Q000378:metabolism; D013799:Theca Cells / Q000201:enzymology
chemical_list: D006063:Chorionic Gonadotropin; D009566:Nitrates; D020030:Nitric Oxide Donors; D009573:Nitrites; D012333:RNA, Messenger; C110881:S-nitro-N-acetylpenicillamine; D013739:Testosterone; D011374:Progesterone; D004958:Estradiol; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496318:Nos2 protein, rat; C496316:Nos3 protein, rat; D010396:Penicillamine