Relationship between type L hormone-sensitive lipase and endogenous triacylglycerol in rat heart.
The purpose of this study was to determine whether, under physiological conditions, intracellular lipoprotein lipase [type L hormone-sensitive lipase (HSL)] activity varied inversely with triacylglycerol (TG) content of the heart. The results show that fasting from 7:30 A.M. to 7:30 P.M. increased type L HSL activity from 72 +/- 1 to 96 +/- 1 U/g wet wt tissue (P less than 0.001) in the myocardium. At the same time, cardiac TG stores decreased from 1.83 +/- 0.03 to 1.37 +/- 0.01 mumol/g tissue (P less than 0.001). In a separate experiment, one night of eating a fat-rich diet (60% of calories from fat) caused a 42% increase in type L HSL activity, which was accompanied by a 42% reduction in the TG content of the heart. Likewise cold exposure (overnight) activated type L HSL (73%) and, at the same time, decreased cardiac TG stores (44%). When data from the fasting, fat-feeding, and cold-exposure experiments were combined, a significant correlation coefficient of -0.81 was obtained between type L HSL activity and TG content of the heart (P less than 0.001). These data provide evidence for a physiological relationship between intracellular lipoprotein lipase activity and cardiac TG content.
D000818:Animals; D003080:Cold Temperature; D004041:Dietary Fats; D005215:Fasting; D006358:Hot Temperature; D007700:Kinetics; D008071:Lipoprotein Lipase / Q000378:metabolism*; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D010477:Perfusion; D051381:Rats; D011919:Rats, Inbred Strains; D014280:Triglycerides / Q000378:metabolism*
D004041:Dietary Fats; D014280:Triglycerides; D008071:Lipoprotein Lipase