Fatty acids reduce heparin-releasable lipoprotein lipase activity
in cultured cardiomyocytes from rat heart.
Anderson, Lorraine G., Rogayah Carroll, H. Stephen Ewart, Anjli
Acharya, and David L. Severson.
Smooth Muscle Research Group, Faculty of Medicine, The University
of Calgary, Calgary, Alberta T2N 4N1, Canada
APStracts 4:0146E, 1997.
Varying glucose and fatty acid (FA) concentrations in the medium of
cultured cardiomyocytes from adult rat hearts were tested for effects
on lipoprotein lipase (LPL) activity. Glucose (5.5, 11 and 25 mM in
the culture medium for 18 - 22 h) had no effect on either heparin
-releasable LPL (HR-LPL) or on cellular LPL (C-LPL) activities. When
cardiomyocytes were cultured overnight with 60 [mu]M oleate, HR-LPL
activity was reduced to 20% of control with no change in C-LPL
activity or total cellular LPL mass. Similar results (HR-LPL and C
-LPL activities) were obtained with 60 [mu]M concentrations of
palmitate and myristate; linoleate and eicosapentaenoate did reduce
C-LPL activity, but the decrease in HR-LPL activity was much greater.
Oxfenicine, a FA oxidation inhibitor, did not alter the inhibitory
effect of 60 [mu]M oleate on HR-LPL. Short-term incubations (1 and 3
h) of cultured cardiomyocytes with 60 [mu]M oleate did not displace
LPL into the medium. Immunodetectable LPL on the cell surface of
oleate-treated cultured cardiomyocytes was increased compared to
control cells but heparin treatment released the same amount of LPL
mass which had reduced catalytic activity.
Received 20 March 1997; accepted in final form 25 June 1997
APS Manuscript Number E128-7.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 24 July 1997