Porcine aortic endothelial cells (PAEC) are known to be metabolically robust. They are capable of surviving extended periods of complete lack of exogenous substrate, and purine release has been shown to be significantly up-regulated. The endogenous substrates used during substrate deprivation, as well as the sources responsible for the increased purine release, have not been completely identified. We tested the possibility that a phosphoglyceroyl-ATP-containing polymer, purinogen, might support PAEC hibernation induced by lack of exogenous substrate. This involved isolation of the acid-insoluble fraction of PAEC, which was presumed to contain purinogen, and analysis by HPLC and 31P NMR. No evidence supporting the presence of triphosphate-containing compounds (purinogen) was found. Similar results were obtained in the rat heart. The majority of the products in the acid-insoluble, alkaline-treated fraction were identified as RNA degradation products (2´- and 3´-nucleoside monophosphates). A [14C]adenosine labelling experiment showed that incorporation of adenosine into the acid-insoluble fraction was almost completely prevented after inhibition of RNA synthesis with actinomycin D. Furthermore, RNA isolated from PAEC and subsequently treated with alkali showed a profile that was almost identical with the HPLC profile of the acid-insoluble fraction. Finally, substrate-free incubation of the cells did not quantitatively or qualitatively influence the distribution of acid-insoluble derivatives. We conclude that PAEC survival during the absence of exogenous substrate is not supported by purinogen but rather by some other, yet-to-be-identified, endogenous substrate.
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March 1999
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Research Article|
February 22 1999
Purinogen is not an endogenous substrate used in endothelial cells during substrate deprivation
Ognjen CULIC;
Ognjen CULIC
1
1Institut für Herz- und Kreislaufphysiologie, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
1To whom correspondence should be addressed (e-mail ognjen@herzkreis.uni-duesseldorf.de).
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Ulrich K. M. DECKING;
Ulrich K. M. DECKING
1Institut für Herz- und Kreislaufphysiologie, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
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Eva BERGSCHNEIDER;
Eva BERGSCHNEIDER
1Institut für Herz- und Kreislaufphysiologie, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
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Jürgen SCHRADER
Jürgen SCHRADER
1Institut für Herz- und Kreislaufphysiologie, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
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Biochem J (1999) 338 (2): 523–527.
Article history
Received:
September 04 1998
Revision Received:
November 26 1998
Accepted:
December 17 1998
Citation
Ognjen CULIC, Ulrich K. M. DECKING, Eva BERGSCHNEIDER, Jürgen SCHRADER; Purinogen is not an endogenous substrate used in endothelial cells during substrate deprivation. Biochem J 1 March 1999; 338 (2): 523–527. doi: https://doi.org/10.1042/bj3380523
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