Changes of insulin like growth factor-I, IGF-I carrier protein in streptozotocin-induced diabetic rat

Heo, Young-ran; Jin, Song-jun; Kim, Jin-shang; Kang, Chang-won

Korean Journal of Veterinary Research 2000;40(3):489-496.

Young-ran Heo¹, Song-jun Jin², Jin-shang Kim², Chang-won Kang²

¹Institute for Molecular Biology and Genetics, Chonbuk National University
²Bio-Safety Research, Chonbuk National University

Streptozotocin에 의해 유도된 당뇨쥐의 IGF-I, IGFBPs 및 IGF-I carrier protein의 변화

허영란¹, 김송군², 김진상², 강창원²

¹전북대학교 유전공학연구소
²전북대학교 생체안전성연구소

Abstract

This study was conducted to investigate the effects of streptozotocin-induced (STZ) diabetes on insulin-like growth factor-I (IGF-I), insulin-like growth factor binding proteins (IGFBPs), and IGF-I carrier proteins in serum, liver, and kidney. The levels of total and free IGF-I were measured by radioimmunoassay (RIA). The patterns of IGFBPs were determined by western ligand blotting (WLB) analysis. The profiles of IGF-I carrier proteins in serum were determined by column chromatography. The levels of total and free IGF-I in serum were lower in STZ-induced diabetic rat than normal rat (p<0.01). Similarly, the levels of total IGF-I in liver was lowered in STZ-induced diabetic rats. On the other hand, the levels of total IGF-I in kidney were increased in STZ-induced diabetic rats compared with normal rats (p<0.01). In serum and liver from STZ-induced diabetic rats, the amount of IGFBP-3 was decreased and the amount of IGFBP-2 was increased compared with normal rats. There was a not difference in amount of IGFBP-4 in serum between STZ-induced diabetic rats and normal rats. The serums of normal rats have higher 150kDa carrier proteins than in STZ-induced diabetic rats, whereas, most of 50kDa carrier proteins were found in STZ-induced diabetic rats. These results demonstrate that in STZ-induced diabetic rats, IGF-I/IGFBPs system that included functional bioactivity was changed in serum as well as tissues, and these changes may play an important role in pathogenesis of diabetes.

Key Words: IGF-I, IGFBPs, IGF-I carrier proteins, diabetes