Diacylglycerols derived from membrane phospholipids are metabolized
by lipases in a10 smooth muscle cells.
Migas, Iris, and David L. Severson.
Smooth Muscle Research Group, Faculty of Medicine, The University
of Calgary, Calgary, Alberta T2N 4N1, Canada
APStracts 3:0137C, 1996.
The metabolic fate of endogenous diacylglycerol (DG) in cultured A10
smooth muscle cells was determined. Pre-incubation of A10 cells with
[3H]myristic acid or [3H]arachidonic acid resulted in preferential
labelling of phosphatidylcholine (PC) or phosphatidylinositol (PI),
respectively. Addition of PC-specific phospholipase C (PC-PLC) to
[3H]myristate-labelled A10 cells resulted in a 10-fold increase in
radiolabelled DG which was converted to monoacylglycerol (MG) and
fatty acid (FA). DG degradation and MG formation was inhibited by
tetrahydrolipstatin, a DG lipase inhibitor. PC-derived DG was not
converted to phosphatidic acid; in addition, PC re-synthesis or TG
synthesis was not observed. Addition of PI-specific phospholipase C
(PI-PLC) to [3H]arachidonate-labelled A10 cells resulted in a modest
increase in radiolabelled DG that was also hydrolyzed to MG and FA.
Therefore, the principal metabolic fate of endogenous DG generated
from membrane phospholipids by treatment of A10 cells with PC-PLC and
PI-PLC was hydrolysis by a DG lipase pathway.
Received 23 January 1996; accepted in final form 19 April 1996.
APS Manuscript Number C51-6.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 8 May 96