Cardiac heparin-releasable lipoprotein lipase activity in fructose-hypertensive rats: effect of coronary vasodilation.
Lipoprotein lipase (LPL) is an endothelium-bound enzyme that is rate determining for the clearance of triacylglycerol-rich lipoproteins. We assessed cardiac heparin-releasable LPL activity in an acquired model of hypertension, the fructose-hypertensive rat. Fructose feeding (10% solution in drinking water ad libitum) for 2 (short-term) or 4-6 (long-term) weeks induced hypertension, hypertriglyceridemia, and hyperinsulinemia in male Wistar rats. After short- and long-term fructose treatment, LPL activity in coronary perfusates was determined by retrogradely perfusing the hearts with heparin. Short-term fructose treatment did not alter cardiac heparin-releasable LPL activity, whereas a significant decrease in LPL activity was seen in the long-term treated group. Discontinuation of fructose treatment for 2 weeks from the long-term group normalized blood pressure and cardiac heparin-releasable LPL activity. Interestingly, acute vasodilation by in vitro perfusion of coronary vasodilators like nifedipine and CGS-21680 increased cardiac heparin-releasable LPL activity in the long-term group to control levels. These studies demonstrate that long-term fructose-induced hypertension may play a significant role in regulating cardiac LPL activity. Whether or not this altered LPL activity has a role in the regulation of fatty acid supply to the hypertensive heart has yet to be determined.
Sambandam
N
N
Division of Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, Canada.
Lim
F
F
Cam
M C
MC
Rodrigues
B
B
D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D001794:Blood Pressure / Q000187:drug effects; D003331:Coronary Vessels / Q000187:drug effects / Q000502:physiology*; D005632:Fructose / Q000633:toxicity; D006493:Heparin / Q000494:pharmacology*; D006973:Hypertension / Q000139:chemically induced / Q000201:enzymology* / Q000503:physiopathology; D066298:In Vitro Techniques; D007328:Insulin / Q000097:blood; D008071:Lipoprotein Lipase / Q000378:metabolism*; D008297:Male; D009131:Muscle, Smooth, Vascular; D009206:Myocardium / Q000201:enzymology*; D009543:Nifedipine / Q000494:pharmacology; D010477:Perfusion; D010627:Phenethylamines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D014280:Triglycerides / Q000097:blood; D014664:Vasodilation / Q000502:physiology*; D014665:Vasodilator Agents / Q000494:pharmacology
D001786:Blood Glucose; D007328:Insulin; D010627:Phenethylamines; D014280:Triglycerides; D014665:Vasodilator Agents; C061282:2-(4-(2-carboxyethyl)phenethylamino)-5'-N-ethylcarboxamidoadenosine; D005632:Fructose; D006493:Heparin; D008071:Lipoprotein Lipase; D009543:Nifedipine; D000241:Adenosine