Chylomicron and palmitate metabolism by perfused hearts from diabetic mice

AS Neitzel, AN Carley… - American Journal of …, 2003 - journals.physiology.org
AS Neitzel, AN Carley, DL Severson
American Journal of Physiology-Endocrinology and Metabolism, 2003journals.physiology.org
Hydrolysis of triacylglycerols (TG) in circulating chylomicrons by endothelium-bound
lipoprotein lipase (LPL) provides a source of fatty acids (FA) for cardiac metabolism. The
effect of diabetes on the metabolism of chylomicrons by perfused mouse hearts was
investigated with db/db (type 2) and streptozotocin (STZ)-treated (type 1) diabetic mice.
Endothelium-bound heparin-releasable LPL activity was unchanged in both type 1 and type
2 diabetic hearts. The metabolism of LPL-derived FA was examined by perfusing hearts with …
Hydrolysis of triacylglycerols (TG) in circulating chylomicrons by endothelium-bound lipoprotein lipase (LPL) provides a source of fatty acids (FA) for cardiac metabolism. The effect of diabetes on the metabolism of chylomicrons by perfused mouse hearts was investigated with db/db (type 2) and streptozotocin (STZ)-treated (type 1) diabetic mice. Endothelium-bound heparin-releasable LPL activity was unchanged in both type 1 and type 2 diabetic hearts. The metabolism of LPL-derived FA was examined by perfusing hearts with chylomicrons containing radiolabeled TG and by measuring 3H2O accumulation in the perfusate (oxidation) and incorporation of radioactivity into tissue TG (esterification). Rates of LPL-derived FA oxidation and esterification were increased 2.3-fold and 1.7-fold in db/db hearts. Similarly, LPL-derived FA oxidation and esterification were increased 3.4-fold and 2.5-fold, respectively, in perfused hearts from STZ-treated mice. The oxidation and esterification of [3H]palmitate complexed to albumin were also increased in type 1 and type 2 diabetic hearts. Therefore, diabetes may not influence the supply of LPL-derived FA, but total FA utilization (oxidation and esterification) was enhanced.
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