Alteration of Insulin-like Growth Factor(IGF)-I and IGF-Binding Proteins in Renal Development and Regeneration

Park, Sung-Kwang; Koh, Gou-Young; Lee, Dae-Yeol

J Korean Soc Pediatr Nephrol > Volume 3(2); 1999 > Article

J Korean Soc Pediatr Nephrol 1999;3(2): 109-116.

신장발육 및 재생에 따른 insulin-like growth factor(IGF)-I 및 IGF-binding protein의 변화

박성광, 고규영, 이대열

¹전북대학교 의과대학 내과학교실, 의과학연구소
²전북대학교 의과대학 심장근재생연구단, 의과학연구소
³전북대학교 의과대학 소아과학교실, 의과학연구소

Alteration of Insulin-like Growth Factor(IGF)-I and IGF-Binding Proteins in Renal Development and Regeneration

Sung-Kwang Park, Gou-Young Koh, Dae-Yeol Lee

¹Department of Internal Medicine, Institute of Medical Science, Chonbuk National University Medical School
²Institute of Cardiac Regeneration Group, Institute of Medical Science, Chonbuk National University Medical School
³Department of Pediatrics, Institute of Medical Science, Chonbuk National University Medical School

ABSTRACT

Purpose: Insulin-like growth factor(IGF)-I and -II are peptide growth factor whose activity is modulated by interaction with the family of six IGF-binding proteins(IGFBPs). IGF-I is detected in rat kidney and has metabolic and growth effects. This study was designed to examine temporal expression of IGFBPs in kidney during renal development and postischemic regeneration in rat.
Method : The expression of IGFBPs in kidney during renal development from 15th day of gestation to adult life by using Northern blot analysis. We also examined the renal IGF-IGFBP axis in uremic rat by using Northern blot and immunohistochemistry.
Results : The mRNA of IGFBP-1 and -3 were not or barely detected in fetal stages. However, the mRNA level of IGFBP-1 and -3 were increased gradually from day 7 after birth to adult. In contrast, the mRNA of IGFBP-2 and -5 were highly expressed in fetal stages and maintained almost same levels until day 7 (IGFBP-2) or day 30 (IGFBP-5) after birth, then their levels decreased markedly. The mRNA of IGFBP-4 were expressed moderately in fetal kidney and increased gradually after birth. Interestingly, the mRNA of IGFBP-1 and-4 were induced up to 3-5 fold during maximum regeneration period and were recovered to normal levels after acute ischemic injury. In contrast, the mRNA level of IGFBP-3 and-IGFBPrP-1 were decreased slightly at 1 day after ischemic injury, then recovered to normal level during maximum regeneration period.
Conclusion : There were differential expressions of IGFBPs in kidney that can modulate IGF action on developing, differentiating, maintaining, and regenerating renal structure and function.