Item – Theses Canada

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OCLC number
54543562
Link(s) to full text
LAC copy
LAC copy
Author
Neitzel, Andrew Scott,1975-
Title
Lipid metabolism in the diabetic heart.
Degree
M. Sc. -- University of Calgary, 2002
Publisher
Ottawa : National Library of Canada = Bibliothèque nationale du Canada, [2003]
Description
2 microfiches.
Notes
Includes bibliographical references.
Abstract
The metabolism of chylomicrons and palmitate was measured in ' ex vivo' perfused working hearts from 12-week old diabetic mice, using both type 1 (streptozotocin induced insulin deficiency) and type 2 (genetic ' db/db') models of diabetes mellitus. Chylomicrons are a lipoprotein produced by the intestine and released into the circulation from the intestinal lymphatics. The triacylglycerol (TG) core of the chylomicron is hydrolyzed by the enzyme lipoprotein lipase (LPL), releasing fatty acids (FA) for uptake by the heart. The amount of LPL on the endothelium of the perfused mouse heart, was measured along with residual tissue activity, neither of which were different in the type 1 (STZ induced) or 2 ('db/db') diabetic hearts compared to control hearts. The utilization (oxidation and esterification) of chylomicrons (LPL-derived FA) and palmitate was significantly increased in the type 1 diabetic hearts. Chylomicron utilization was measured in the type 2 diabetic hearts and was also found to be significantly elevated. Since LPL levels were not different between the diabetic hearts and control hearts, increases in chylomicron metabolism must be the result of downstream metabolic alterations, which produce a similar increase in palmitate utilization. Increases in fatty acid metabolism were accompanied by reductions in cardiac contractile function in both models of diabetes. This is the first study to measure chylomicron metabolism in either a type 1 or 2 diabetic mouse model. In addition, palmitate metabolism in the type 1 diabetic mouse model has not been previously reported. These findings are novel as they provide evidence that there is a cardiomyopathy associated with a dysregulation of metabolism in the diabetic heart.
ISBN
0612762467
9780612762466