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

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

  • Heo, Young-ran (Institute for Molecular Biology and Genetics, Chonbuk National University) ;
  • Jin, Song-jun (Bio-Safety Research, Chonbuk National University) ;
  • Kim, Jin-shang (Bio-Safety Research, Chonbuk National University) ;
  • Kang, Chang-won (Bio-Safety Research, Chonbuk National University)
  • 허영란 (전북대학교 유전공학연구소) ;
  • 김송군 (전북대학교 생체안전성연구소) ;
  • 김진상 (전북대학교 생체안전성연구소) ;
  • 강창원 (전북대학교 생체안전성연구소)
  • Received : 2000.08.07
  • Published : 2000.09.25

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.

본 연구에서는 Streptozotocin-induced 당뇨가 혈청과 간장 및 신장조직의 IGF-I, IGFBPs 및 IGF-I carrier protein 특성에 미치는 영향을 조사하였다. 혈액과 조직중의 IGF-I 농도는 방사면역측정법으로 측정하였고, IGFBPs 양상은 Western Ligand Blotting(WLB)으로 관찰하였으며, IGF-I carrier protein의 특성은 column chromatography로 측정하였다. 혈청과 IGF-I 농도는 당뇨군이 대조군에 비하여 유의하게 감소하였다 (p<0.01). 당뇨군은 대조군에 비하여 간장 IGF-I 농도는 유의하게 감소한 반면, 신장의 IGF-I 농도는 유의하게 증가하였다(p<0.01). 당뇨군은 대조군에 비하여 혈청과 간장의 IGFBP-3는 감소한 반면, IGFBP-2는 증가하였고, IGFBP-4는 변화가 없었다. 또한 당뇨군은 대조군에 비하여 150kDa carrier protein은 감소하였으며, 50kDa carrier protein은 증가하였다. 이상의 결과를 종합해볼 때 Streptozotocin-induced 당뇨는 혈청 뿐만 아니라 조직의 IGF-I/IGFBP system 변동에 영향을 미침을 알 수 있었다.

Keywords