Rodrigues B, Braun J E, Spooner M, Severson D L
Medical Research Council of Canada Signal Transduction Group, Faculty of Medicine, University of Calgary, Alta.
Can J Physiol Pharmacol. 1992 Sep;70(9):1271-9. doi: 10.1139/y92-176.
The objective of this investigation was to test the hypothesis that the diabetes-induced reduction in lipoprotein lipase activity in cardiac myocytes may be due to hypertriglyceridemia. Administration of 4-aminopyrazolopyrimidine (50 mg/kg) to control rats for 24 h reduced plasma triacylglycerol levels and increased the heparin-induced release of lipoprotein lipase into the incubation medium of cardiac myocytes. The acute (3-5 days) induction of diabetes by streptozotocin (100 mg/kg) produced hypertriglyceridemia and reduced heparin-releasable lipoprotein lipase activity in cardiac myocytes. Treatment of diabetic rats with 4-aminopyrazolopyrimidine resulted in a fall in plasma triacylglycerol content and increased heparin-releasable lipoprotein lipase activity. Administration of Triton WR-1339 also resulted in hypertriglyceridemia, but the heparin-induced release of lipoprotein lipase from control cardiac myocytes was not reduced in the absence of lipolysis of triacylglycerol-rich lipoproteins. Treatment with Triton WR-1339 did, however, increase the heparin-induced release of lipoprotein lipase from diabetic cardiac myocytes. Preparation of cardiac myocytes with 0.9 mM oleic acid resulted in a decrease in both total cellular and heparin-releasable lipoprotein lipase activities. These results suggest that the diabetes-induced reduction in heart lipoprotein lipase activity may, at least in part, be due to an inhibitory effect of free fatty acids, derived either from lipoprotein degradation or from adipose tissue lipolysis, on lipoprotein lipase activity in (and (or) release from) cardiac myocytes.
糖尿病导致心肌细胞中脂蛋白脂肪酶活性降低可能是由于高甘油三酯血症。给对照大鼠注射4-氨基吡唑并嘧啶（50 mg/kg）24小时可降低血浆甘油三酯水平，并增加肝素诱导的脂蛋白脂肪酶释放到心肌细胞孵育培养基中的量。链脲佐菌素（100 mg/kg）急性诱导糖尿病（3 - 5天）会导致高甘油三酯血症，并降低心肌细胞中肝素可释放的脂蛋白脂肪酶活性。用4-氨基吡唑并嘧啶治疗糖尿病大鼠会导致血浆甘油三酯含量下降，并增加肝素可释放的脂蛋白脂肪酶活性。给予Triton WR-1339也会导致高甘油三酯血症，但在富含甘油三酯的脂蛋白不发生脂解的情况下，对照心肌细胞中肝素诱导的脂蛋白脂肪酶释放并未减少。然而，用Triton WR-1339治疗确实增加了糖尿病心肌细胞中肝素诱导的脂蛋白脂肪酶释放。用0.9 mM油酸处理心肌细胞会导致总细胞和肝素可释放的脂蛋白脂肪酶活性均下降。这些结果表明，糖尿病导致的心脏脂蛋白脂肪酶活性降低可能至少部分是由于来自脂蛋白降解或脂肪组织脂解的游离脂肪酸对心肌细胞中脂蛋白脂肪酶活性（和/或从心肌细胞释放）的抑制作用。
