糖尿病对骨骼肌和心脏中鸟嘌呤核苷酸交换因子活性的影响。

Effect of diabetes on guanine nucleotide exchange factor activity in skeletal muscle and heart.

作者信息

Kimball S R, Jefferson L S

机构信息

Department of Physiology, College of Medicine, Pennsylvania State University, Hershey Medical Center, Hershey 17033.

出版信息

Biochem Biophys Res Commun. 1988 Oct 31;156(2):706-11. doi: 10.1016/s0006-291x(88)80900-8.

DOI:10.1016/s0006-291x(88)80900-8

PMID:3056401

Abstract

The present study examined the effects of diabetes and insulin treatment of diabetic rats on the activity of the protein synthesis initiation factor, the guanine nucleotide exchange factor. In extracts from gastrocnemius and psoas muscles from two-day diabetic rats, guanine nucleotide exchange factor activity was reduced to 80% and 67% of control values, respectively. Insulin treatment (2 h) restored guanine nucleotide exchange factor activity to control values in both muscles. In contrast, guanine nucleotide exchange factor activity was unchanged in extracts from either soleus muscle or heart from diabetic rats compared to controls. Also, insulin treatment did not increase guanine nucleotide exchange factor activity in extracts from soleus and heart. The results suggest that the diabetes-induced impairment in peptide-chain initiation in fast-twitch skeletal muscle (i.e. gastrocnemius and psoas) is related to an inhibition of guanine nucleotide exchange factor activity and that slow-twitch muscle is spared from the effect on initiation due to the preservation of guanine nucleotide exchange factor activity.

摘要

本研究检测了糖尿病及胰岛素治疗对糖尿病大鼠蛋白质合成起始因子（鸟嘌呤核苷酸交换因子）活性的影响。在两日龄糖尿病大鼠的腓肠肌和腰大肌提取物中，鸟嘌呤核苷酸交换因子活性分别降至对照值的80%和67%。胰岛素治疗（2小时）使两块肌肉中的鸟嘌呤核苷酸交换因子活性恢复至对照值。相比之下，与对照组相比，糖尿病大鼠比目鱼肌或心脏提取物中的鸟嘌呤核苷酸交换因子活性没有变化。此外，胰岛素治疗并未增加比目鱼肌和心脏提取物中的鸟嘌呤核苷酸交换因子活性。结果表明，糖尿病诱导的快收缩骨骼肌（即腓肠肌和腰大肌）肽链起始受损与鸟嘌呤核苷酸交换因子活性受到抑制有关，而慢收缩肌肉因鸟嘌呤核苷酸交换因子活性得以保留而免受起始作用的影响。