Pierce G N, Dhalla N S
Am J Physiol. 1983 Sep;245(3):C241-7. doi: 10.1152/ajpcell.1983.245.3.C241.
Heart sarcolemmal membranes were isolated by the hypotonic shock-LiBr treatment from rats with chronic diabetes induced by a streptozotocin (65 mg/kg, iv) injection. Sarcolemmal Mg2+-dependent ATPase activity was elevated, whereas 5'-nucleotidase and K+-p-nitrophenylphosphatase activities in diabetic heart were depressed in comparison to control preparations. Although patent Na+-K+-ATPase and patent ouabain-sensitive Na+-K+-ATPase activities were unaltered, latent Na+-K+-ATPase activities, as determined in membranes after alamethicin or deoxycholate treatments, were found to be significantly depressed in diabetic animals. A depression in the latent Na+-K+-ATPase activity in diabetic preparations was also observed in membranes prepared by the sucrose density gradient method. Insulin-treated diabetic rats were observed to have normalized latent Na+-K+-ATPase activities. Total phospholipid content did not differ, but cholesterol content of the sarcolemmal membranes was significantly increased in diabetic heart preparations. Sarcolemmal Na+-K+-ATPase activity in diabetic heart was more resistant to treatments with filipin, an agent known to bind with cholesterol residues. These results suggest that chronic experimental diabetes is associated with some defects in sarcolemmal enzymatic activities and composition.
通过低渗休克-LiBr处理从经链脲佐菌素（65mg/kg，静脉注射）诱导的慢性糖尿病大鼠中分离出心脏肌膜。与对照制剂相比，糖尿病心脏中肌膜Mg2+依赖性ATP酶活性升高，而5'-核苷酸酶和K+-对硝基苯磷酸酶活性降低。尽管专利Na+-K+-ATP酶和专利哇巴因敏感的Na+-K+-ATP酶活性未改变，但在经阿拉霉素或脱氧胆酸盐处理后的膜中测定的潜在Na+-K+-ATP酶活性在糖尿病动物中显著降低。在通过蔗糖密度梯度法制备的膜中也观察到糖尿病制剂中潜在Na+-K+-ATP酶活性降低。观察到胰岛素治疗的糖尿病大鼠潜在Na+-K+-ATP酶活性正常化。总磷脂含量没有差异，但糖尿病心脏制剂中肌膜的胆固醇含量显著增加。糖尿病心脏中的肌膜Na+-K+-ATP酶活性对与胆固醇残基结合的剂制霉菌素的处理更具抗性。这些结果表明，慢性实验性糖尿病与肌膜酶活性和组成的某些缺陷有关。
