Document Detail


A reversible, hydrogen ion blockade of spontaneous oocyte maturation in the starfish: locus of action.
MedLine Citation:
PMID:  9467     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Starfish (Asterias forbesi) oocytes encased within their follicle cells mature spontaneously during a portion of the normal reproductive period when released from the ovary into seawater. A previous report has shown that oocytes isolated in acidic seawater do not mature spontaneously but retain the capacity to do so when returned to normal seawater. The object of this study was to determine the mechanism by which acidic pH reversibly blocks spontaneous oocyte maturation in isolated follicles. Incidence of spontaneous oocyte maturation in follicles isolated in acidic seawater decreased as pH decreased from 7 to 4. Oocytes in which spontaneous maturation was inhibited (ASW at pH 4.7 TO 5.4) underwent germinal vesicle breakdown with the addition of 1-methyladenine. Oocytes isolated in acidic seawater (pH 4 or 5) with intact follicle cells matured spontaneously when transferred immediately to normal seawater pH 8); after four hours, 60-65% of the follicles incubated in seawater at pH 5 matured spontaneously when returned to normal seawater as compared to less than 10% of the follicles maintained at pH 4. Inhibition of spontaneous maturation was not reversible in the absence of the follicle cells. Oocytes isolated in acidic seawater with their follicle cells did not spontaneously mature when transferred to calcium-free seawater at pH 8. The results obtained support the hypothesis that acidic seawater reversibly inhibits spontaneous oocyte maturation by interfering with the release of meiosis-inducing substance from the follicle cells.
Authors:
J G Cloud; A W Schuetz
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of experimental zoology     Volume:  197     ISSN:  0022-104X     ISO Abbreviation:  J. Exp. Zool.     Publication Date:  1976 Sep 
Date Detail:
Created Date:  1976-12-01     Completed Date:  1976-12-01     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0375365     Medline TA:  J Exp Zool     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  357-62     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Animals
Calcium / pharmacology
Female
Hydrogen / pharmacology
Hydrogen-Ion Concentration
Oocytes / drug effects,  physiology*
Ovarian Follicle / physiology
Ovum / physiology*
Seawater
Starfish
Chemical
Reg. No./Substance:
1333-74-0/Hydrogen; 7440-70-2/Calcium

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


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