Salhanick A I, West H, Amatruda J M
J Biol Chem. 1985 Dec 25;260(30):16232-6.
The mechanism underlying the increased insulin binding found in hepatic plasma membranes from streptozotocin-diabetic rats was evaluated by measuring insulin binding to intact and Triton X-100-soluble extracts of plasma membranes prepared from the livers of control rats and rats administered streptozotocin (85 mg/kg). In addition, to assess whether the cellular content of hepatic insulin receptors is also increased in diabetic animals, we measured insulin-binding activity in intact and soluble extracts of total hepatic cellular membrane preparations (100,000 X g cellular pellets). The data indicate that while insulin binding is increased (52 +/- 3%) in intact hepatic plasma membranes from diabetic rats compared to control rats, there is no comparable increase in insulin binding in intact total cellular membranes or in Triton X-100-soluble extracts of plasma membranes or total cellular membranes. We therefore conclude that the enhanced insulin binding found in the livers of diabetic rats is the result of a local redistribution of plasma membrane insulin receptors from cryptic to exposed sites. Finally, the data suggest the presence of a negative modulator of insulin-binding affinity in intact plasma and total cellular membranes.
通过测量胰岛素与从对照大鼠和注射链脲佐菌素（85mg/kg）的大鼠肝脏制备的完整质膜以及Triton X-100可溶性质膜提取物的结合，评估了链脲佐菌素诱导的糖尿病大鼠肝质膜中胰岛素结合增加的潜在机制。此外，为了评估糖尿病动物肝脏胰岛素受体的细胞含量是否也增加，我们测量了完整的和可溶的全肝细胞膜制剂（100,000×g细胞沉淀）中的胰岛素结合活性。数据表明，与对照大鼠相比，糖尿病大鼠完整肝质膜中的胰岛素结合增加（52±3%），但完整全细胞膜或质膜或全细胞膜的Triton X-100可溶提取物中的胰岛素结合没有相应增加。因此，我们得出结论，糖尿病大鼠肝脏中增强的胰岛素结合是质膜胰岛素受体从隐匿部位向暴露部位局部重新分布的结果。最后，数据表明完整质膜和全细胞膜中存在胰岛素结合亲和力的负调节剂。
