Acute diabetes does not reduce heparin-releasable lipoprotein lipase activity in perfused hearts from Wistar-Kyoto rats.
The induction of diabetes (3-5 days duration) in Wistar-Kyoto rats by the administration of streptozotocin (100 mg/kg) did not increase plasma concentrations of triacylglycerols or free fatty acids, and did not reduce heparin-releasable (functional) lipoprotein lipase activity in perfused hearts. By comparison, diabetic Sprague-Dawley rats were characterized as having hypertriglyceridemia and decreased heparin-releasable lipoprotein lipase activity in perfused hearts. Therefore, the diabetes-induced reduction in myocardial lipoprotein lipase activity in Sprague-Dawley rat hearts may, at least in part, be a compensatory response to the hypertriglyceridemia and increased fatty acid delivery to the myocardial cell, which is a characteristic feature of most severe, insulin-deficient models of diabetes mellitus. Although functional, endothelium-bound lipoprotein lipase activity was not reduced in diabetic perfused hearts from Wistar-Kyoto rats, cellular and heparin-releasable lipoprotein lipase activity was reduced in cardiac myocyte preparations, suggesting that other mechanisms in addition to plasma triacylglycerol must regulate lipoprotein lipase activity in the whole diabetic Wistar-Kyoto rat heart and that cardiac myocytes may not be the exclusive source of functional lipoprotein lipase in the diabetic myocardium.
Rodrigues
B
B
Medical Research Council of Canada Signal Transduction Group, Faculty of Medicine, University of Calgary, AB.
Severson
D L
DL
D000208:Acute Disease; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000201:enzymology*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D006493:Heparin / Q000494:pharmacology*; D015228:Hypertriglyceridemia / Q000097:blood; D066298:In Vitro Techniques; D008071:Lipoprotein Lipase / Q000378:metabolism*; D008297:Male; D009206:Myocardium / Q000201:enzymology* / Q000378:metabolism; D010477:Perfusion; D051381:Rats; D011921:Rats, Inbred WKY; D017207:Rats, Sprague-Dawley; D014280:Triglycerides / Q000097:blood
D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D014280:Triglycerides; D006493:Heparin; D008071:Lipoprotein Lipase