β-adrenergic stimulation of fatty acid release from brown fat cells differentiated in monolayer culture

Brown fat cells, freshly isolated from cold-acclimated hamsters and rats, did not respond to norepinephrine addition with the characteristic increase in oxygen consumption (heat production) seen in cells from control animals. However, incubation of these cells for 1 h in a Krebs-Ringer bicarbonate buffer, in the presence of 10 mM pyruvate, fully restored norepinephrine responsiveness. Cells treated in this way from cold-acclimated hamsters (a hibernator) increased the rate of oxygen consumption after maximal norepinephrine stimulation as much as cells from control hamsters; also norepinephrine-stimulated fatty acid release was unaltered, indicating that brown fat cells may partly be responsible for the increase in serum fatty acid level seen during arousal from hibernation. Similarly, preincubated cells from cold-acclimated rats (a nonhibernator) increased oxygen consumption and fatty acid release as much as cells from control rats; this suggests that also in cold-acclimated rats brown fat may supply the circulation with fatty acids during cold stress. Cells from cold-acclimated animals were, however, about 10 times less sensitive to norepinephrine than cells from control animals; this desensitization may be the result of a stimulated phosphodiesterase.

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A model-fitting procedure to accommodate the progress of hormone-stimulated non-esterified fatty acid release by rat epididymal fat-cells

Biochemical Society Transactions ◽

10.1042/bst0090562 ◽

1981 ◽

Vol 9 (6) ◽

pp. 562-563

Author(s):

J. ISLWYN DAVIES ◽

ROBERT C. MUDD

Keyword(s):

Fatty Acid ◽

Model Fitting ◽

Fat Cells ◽

Fitting Procedure ◽

Epididymal Fat ◽

Fatty Acid Release ◽

Acid Release

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Eicosapentaenoic and dihomo gamma linolenic acid metabolism by cultured rat mesangial cells

AJP Cell Physiology ◽

10.1152/ajpcell.1989.256.1.c101 ◽

1989 ◽

Vol 256 (1) ◽

pp. C101-C108 ◽

Cited By ~ 13

Author(s):

L. A. Scharschmidt ◽

N. B. Gibbons ◽

R. Neuwirth

Keyword(s):

Fatty Acids ◽

Fatty Acid ◽

Acid Metabolism ◽

Mesangial Cells ◽

Gamma Linolenic Acid ◽

Significant Extent ◽

Glomerular Function ◽

Fatty Acid Release ◽

Acid Release ◽

Stimulation Of

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.

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