Document Detail


In vitro effects of arachidonic acid on the prostaglandin synthesizing system in gastric mucosa.
MedLine Citation:
PMID:  1908110     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Self-destruction of the prostaglandin cyclooxygenase has been suggested to be an important factor in the regulation of endogenous prostaglandin synthesis. The present study was done in order to define the role of this substrate-induced inactivation in the regulation of prostaglandin synthesis in gastric mucosa. In tissue homogenate, the prostaglandin synthesizing capacity is rapidly inactivated at 37 degrees C, even in the absence of exogenous arachidonic acid. It was shown that this inactivation can be prevented both by EDTA as a chelator of calcium-ions and by tetracaine, a specific inhibitor of the phospholipase A2. Additional exogenous arachidonic acid again inactivated prostaglandin synthesis in a dose dependent manner. In contrast, the prostaglandin synthesizing capacity in organ cultured mucosal biopsies is well preserved, although the release of endogenous substrate was activated by extracellular calcium and Ca-ionophore A23187. Furthermore, even at high concentrations of exogenous arachidonic acid present in the culture medium, the synthesizing capacity in intact biopsies was only slightly and reversibly reduced. These large differences between intact biopsies and cell free tissue preparations point to very efficient mechanisms controlling the substrate availability for the cyclooxygenase system both from endogenous and exogenous sources in intact gastric mucosa.
Authors:
G Preclik; E F Stange; D Arnold; H Ditschuneit
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Prostaglandins     Volume:  41     ISSN:  0090-6980     ISO Abbreviation:  Prostaglandins     Publication Date:  1991 Apr 
Date Detail:
Created Date:  1991-09-13     Completed Date:  1991-09-13     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  0320271     Medline TA:  Prostaglandins     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  359-73     Citation Subset:  IM    
Affiliation:
University of Ulm, Department of Internal Medicine II, Germany.
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MeSH Terms
Descriptor/Qualifier:
Animals
Arachidonic Acid
Arachidonic Acids / metabolism,  pharmacology*
Calcium Chloride / pharmacology
Cycloheximide / pharmacology
Edetic Acid / pharmacology
Gastric Mucosa / drug effects,  metabolism*
Hydrogen Peroxide / pharmacology
Male
Organ Culture Techniques
Prostaglandins / biosynthesis*,  metabolism
Rabbits
Radioimmunoassay
Tetracaine / pharmacology
Tissue Extracts
Chemical
Reg. No./Substance:
0/Arachidonic Acids; 0/Prostaglandins; 0/Tissue Extracts; 10043-52-4/Calcium Chloride; 506-32-1/Arachidonic Acid; 60-00-4/Edetic Acid; 66-81-9/Cycloheximide; 7722-84-1/Hydrogen Peroxide; 94-24-6/Tetracaine

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


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