Expression and localization of inducible and endothelial nitric oxide synthase in the rat ovary. Effects of gonadotropin stimulation in vivo.
Nitric oxide is reportedly involved in the regulation of several ovarian processes, yet the isoforms of nitric oxide synthase (NOS) expressed in the ovary are unknown. Our purpose was to identify and localize NOS isoenzymes in the rat ovary and to examine++ if mRNA expression of NOS isoenzymes change after gonadotropin stimulation. Using reverse transcriptase-PCR, we demonstrated that inducible (iNOS) and endothelial (eNOS), but not neuronal, NOS mRNAs are expressed in the ovary. In a gonadotropin-stimulated rat model, unstimulated ovaries had the highest levels of iNOS mRNA as quantified by ribonuclease protection assay. After gonadotropin injection, iNOS mRNA declined to undetectable levels in ovaries containing ovulatory follicles before increasing slighty in ovaries containing copora lutea. In situ hybridization studies localized iNOS to granulosa cells of secondary follicles and small antral follicles. Western blots of unstimulated ovaries demonstrated iNOS protein. In contrast to iNOS, eNOS mRNA levels, determined by quantitative PCR, increased after gonadotropin stimulation and peaked in ovaries containing ovulatory follicles before declining in the luteal phase. eNOS protein was localized to blood vessels in the ovary by immunohistochemistry. We conclude that two isoforms of NOS are expressed in the ovary and the mRNA levels for these isozymes are differentially regulated.
Van Voorhis
B J
BJ
Department of Obstetrics and Gynecology, University of Iowa College of Medicine, Iowa City 52242-1080, USA.
Moore
K
K
Strijbos
P J
PJ
Nelson
S
S
Baylis
S A
SA
Grzybicki
D
D
Weiner
C P
CP
D000818:Animals; D001483:Base Sequence; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D003338:Corpus Luteum / Q000201:enzymology; D017931:DNA Primers; D004730:Endothelium, Vascular / Q000201:enzymology; D004971:Estrus; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007527:Isoenzymes / Q000032:analysis / Q000096:biosynthesis*; D008969:Molecular Sequence Data; D009474:Neurons / Q000201:enzymology; D019001:Nitric Oxide Synthase / Q000032:analysis / Q000096:biosynthesis*; D006080:Ovarian Follicle / Q000201:enzymology; D010053:Ovary / Q000187:drug effects / Q000201:enzymology*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley
D006063:Chorionic Gonadotropin; D017931:DNA Primers; D007527:Isoenzymes; D012333:RNA, Messenger; D019001:Nitric Oxide Synthase