AJP - Cell Physiology, Vol 256, Issue 1 C101-C108, Copyright © 1989 by American Physiological Society
Eicosapentaenoic and dihomo gamma linolenic acid metabolism by cultured rat mesangial cells
L. A. Scharschmidt, N. B. Gibbons and R. Neuwirth
Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461.
To better understand the effects of dietary fatty acid manipulations on
glomerular function, we compared mesangial incorporation, release, and
metabolism of arachidonic (AA), eicosapentaenoic (EPA), and dihomo gamma
linolenic (DHG) acids. We found marked differences in mesangial handling of
these fatty acids. AA was incorporated into lipids of mesangial cells much
more rapidly than EPA or DHG. Ionophore-induced stimulation of fatty acid
release from mesangial cells prelabeled with [14C]AA, [14C]EPA, or [14C]DHG
caused a release of labeled AA greater than DHG much less than EPA,
respectively. Preloading mesangial cells with DHG or EPA for 24 h reduced
subsequent basal, ionophore-, and hormone-stimulated prostaglandin E2
(PGE2) synthesis. Finally, unlike AA, neither EPA nor DHG was converted to
a significant extent by mesangial cyclooxygenase or lipoxygenase. Thus the
mesangial metabolism of DHG and EPA differs both quantitatively and
qualitatively from that of AA. Furthermore, EPA and DHG inhibit metabolism
of AA at the level of mesangial cyclooxygenase.
