Document Detail

Changes in phospholipase A2 in myometrium of the guinea pig uterus during pregnancy.
MedLine Citation:
PMID:  1307379     Owner:  NLM     Status:  MEDLINE    
Phospholipase A2 activity has been measured in membrane and cytosolic fractions from non-pregnant and pregnant guinea pig myometrium has been studied. Enzyme activity was measured with 1-stearoyl-2- [3H]arachidonoyl-phosphatidylcholine exhibiting Michaelis-Menton kinetics with Km of 83.8 +/- 21.6 and 53.2 +/- 14.1 for membrane and cytosolic enzymes respectively. Fractionation of the myometrium from non-pregnant guinea pigs suggested that 35% of the activity was membrane associated compared with 20% (P < 0.01) in tissue from pregnant animals. In the presence of 1 mM calcium total activity rose from 3.03 +/- 0.41 to 1737 +/- 368 nmol/h per uterus between non-pregnant and late pregnancy. Calcium activated the membrane enzyme, but the effect was greater late in pregnancy with almost a 6-fold increase in activity at 1 mM calcium compared with a doubling in membrane from non-pregnant guinea pigs. The K0.5 for calcium activation was about 150 microM. Immunoblotting with anti-human-110 KDa phospholipase A2 showed in guinea pig uterus a 34 KDa form of the enzyme that, consistent with changes in activity, showed a fifteen-fold increase in quantity between non-pregnant and late pregnancy. The data are consistent with dramatic increases in the capacity for arachidonic acid release and prostaglandin production in the guinea pig myometrium late in pregnancy.
A Khouja; C T Jones
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of developmental physiology     Volume:  18     ISSN:  0141-9846     ISO Abbreviation:  J. Dev. Physiol.     Publication Date:  1992 Dec 
Date Detail:
Created Date:  1993-09-02     Completed Date:  1993-09-02     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  7910737     Medline TA:  J Dev Physiol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  271-7     Citation Subset:  IM    
Laboratory of Cellular and Developmental Physiology, University of Oxford, John Radcliffe Hospital, UK.
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MeSH Terms
Arachidonic Acid / metabolism*
Calcium / pharmacology*
Cell Membrane / enzymology
Enzyme Activation
Guinea Pigs
Myometrium / enzymology*
Phosphatidylcholines / metabolism
Phospholipases A / metabolism*
Phospholipases A2
Pregnancy, Animal / metabolism*
Reg. No./Substance:
0/Phosphatidylcholines; 18892-74-5/1-stearoyl-2-arachidonylphosphatidylcholine; 506-32-1/Arachidonic Acid; 7440-70-2/Calcium; EC 3.1.1.-/Phospholipases A; EC A2

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

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