GROWTH FACTOR BINDING PROTEINS & INHIBITORS IN DIABETES

胰岛素样生长因子（IGF或生长调节素）活性降低， 糖尿病可能导致生长减缓、伤口愈合不良， 肛门受损。 虽然血液中的IGF水平可能很低，但循环水平 的IGF抑制剂是高的，并可能进一步降低净IGF活性， 糖尿病 因为抑制剂在大小上相似（分子量20- 30）， 40 kDa）到最近表征的IGF结合蛋白（BP），我们问 BP的变化是否可能导致高循环抑制性 糖尿病活动。 通过Sephacryl S-200色谱分析， 亲和标记技术证实，由于蛋白质的变化， 链脲佐菌素中适当分子量（20至50 kDA）的BP- 糖尿病动物 我们现在应用配体印迹，免疫印迹， 免疫沉淀和北方印迹技术来鉴定特异性 32 kDa BP负责糖尿病的这些变化， 不同于先前表征的低分子量IGF BP 存在于胎鼠血清中（BP-3A）。 由于32 kDa BP被归一化， 胰岛素治疗，这些BPS的调节可能代表一种机制， 胰岛素和其他激素可以调节生长过程， 在糖尿病和其他疾病状态下的抗氧化剂。 为了进一步研究 这种可能性，现在将开发具体的工具来检查 32 kDa BP在体内和体外的调节机制。 我们最近 观察到，具有免疫应答的高分化H4 IIE大鼠 肝癌细胞系在滚瓶培养中分泌这种32 kDa蛋白 将极大地促进BP纯化，并为初始输入提供模型 调控的体外研究。 纯化的BP将用于制备特定的 以获得用于后续开发的氨基酸序列数据 的cDNA探针，以研究BP调节的具体机制， 完整的动物和分离的细胞 因为肝脏似乎是一个 IGF-BP及其抑制物产生重要部位，晚期肝32 kDA-BP 生产，注意力将集中在确定激素和/或 调节肝脏32 kDa BP产生的代谢因子， 关于BP具体机制的后续研究的基础 调控 由于IGFs是许多细胞类型的生长调节剂， 现在提出的，应该提供更好的理解细胞的调节， 糖尿病的生长和其他合成代谢过程，以及其他代谢 疾病

Reduced insulin-like growth factor (IGF, or somatomedin) activity in diabetes may contribute to decreased growth, poor wound healing, and impaired anabolism. While blood IGF levels may be low, circulating levels of IGF inhibitors are high and may further reduce net IGF activity in diabetes. Because inhibitors are similar in size (molecular weight 20- 40kDa) to recently characterized IGF binding proteins (BPs), we asked whether changed in BPs may contribute to high circulating inhibitory activity in diabetes. Analysis by Sephacryl S-200 chromatography and affinity labeling techniques confirmed a marked increase sue to changes in BPs of appropriate molecular weight (20 to 50kDA) in streptozotocin- diabetic animals. We now have applied ligand blot, immunoblot, immunoprecipitation, and northern blot techniques to identify a specific 32kDa BP that is responsible for these changes in diabetes, and is distinct from the previously characterized low molecular weight IGF BP present in fetal rat serum (BP-3A). Since 32kDa BPs are normalized by insulin therapy, regulation of these BPS may represent one mechanism by which insulin, and other hormones, may modulate growth processes and anabolism in diabetes and other disease states. To further investigate this possibility, specific tools will now be developed to examine mechanisms of 32kDa BP regulation in vivo and in vitro. Our recent observation that the hormone-responsive, well differentiated H4IIE rat hepatoma cell line secretes this 32kDa protein in roller bottle culture will greatly facilitate BP purification and provide a model for initial in vitro studies of regulation. Purified BP will be used to prepare specific antiserum and to obtain amino acid sequence data for subsequent development of cDNA probes to investigate specific mechanisms of BP regulation in intact animals, and isolated cells. Since the liver appears to be an important site of IGF BP and inhibitor production, late hepatic 32kDA BP production, attention will be focused on identifying hormonal and/or metabolic factors that modulate hepatic 32kDa BP production, providing the basis for subsequent investigations regarding specific mechanisms of BP regulation. Since IGFs are growth regulators for many cell types, studies now proposed should provide better understanding of the regulation of cell growth and other anabolic processes in diabetes, and other metabolic diseases.