Document Detail

Prostaglandin endoperoxide synthase in rat ovarian follicles: content, cellular distribution, and evidence for hormonal induction preceding ovulation.
MedLine Citation:
PMID:  3109886     Owner:  NLM     Status:  MEDLINE    
These studies were undertaken to determine if the content of prostaglandin endoperoxide (PGH) synthase (PGS) was regulated in rat ovarian follicles in a time-, tissue-, and dose-dependent manner. For quantitation and localization of the enzyme by immunoblot and immunofluorescent analyses, respectively, a polyclonal antibody to highly purified (95%) ovine seminal vesicle PGS [mol wt, (Mr), 72,000] was generated in a rabbit, and an immunoglobulin G fraction of the antiserum was purified by elution from a PGS affinity resin. Soluble cell extracts were prepared from: 1) small antral (SA) and preovulatory (PO) rat follicles before and at selected time intervals after exposure to increasing doses (0.25-10.0 IU) of hCG, 2) granulosa and thecal cells of these same follicles, and 3) granulosa cells of hypophysectomized (H) rats before and after treatment with estradiol (HE), estradiol and FSH (HEF), and 10 IU hCG. Immunoblot analyses demonstrated that the content of PGS (Mr, 72,000) was low (negligible) in granulosa and thecal cells of SA and PO follicles, was induced preferentially (approximately 15-fold) in granulosa cells between 1 and 7 h after hCG treatment (0.5, 2.0, or 10 IU), and declined between 12-24 h after administration of 10 IU hCG, reaching undetectable amounts in corpora lutea isolated 48 h after hCG treatment. PGS (Mr, 72,000) was also induced by 10 IU hCG in granulosa cells of HEF rats, but was low in granulosa cells of H, HE, and HEF rats. In contrast, prostacyclin synthase was present in granulosa cells of preantral (H and HE rats), SA, and PO follicles, was not induced by hCG, and was highest in thecal cells. Immunofluorescent analyses confirmed both the tissue-specific localization and induction of PGS in granulosa cells of rat PO follicles treated with 10 IU hCG and the subcellular fractionation analyses showing that the PGS that was induced by hCG was localized primarily to a membrane (plasma membrane?) fraction of granulosa cells. Immunofluorescent data also demonstrated immunoreactive PGS in the vascular tissue of the rat corpus luteum but not in the luteal cells. Results of these studies document unequivocally that the synthesis of prostaglandins that is increased by LH/hCG in rats preceding ovulation is associated with an increased PGS content, that induction of the induced enzyme is transient, and that the enzyme is primarily localized to granulosa cell membrane fractions.
L Hedin; D Gaddy-Kurten; R Kurten; D L DeWitt; W L Smith; J S Richards
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Endocrinology     Volume:  121     ISSN:  0013-7227     ISO Abbreviation:  Endocrinology     Publication Date:  1987 Aug 
Date Detail:
Created Date:  1987-08-25     Completed Date:  1987-08-25     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0375040     Medline TA:  Endocrinology     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  722-31     Citation Subset:  AIM; IM    
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MeSH Terms
Cell Fractionation
Chorionic Gonadotropin / pharmacology*
Electrophoresis, Polyacrylamide Gel
Enzyme Induction / drug effects
Granulosa Cells / enzymology
Immunologic Tests
Ovarian Follicle / enzymology*,  growth & development,  ultrastructure
Prostaglandin-Endoperoxide Synthases / metabolism*
Subcellular Fractions / enzymology
Theca Cells / enzymology
Grant Support
Reg. No./Substance:
0/Chorionic Gonadotropin; EC Synthases

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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