Transient increase in renal insulin-like growth factor binding proteins during initial kidney hypertrophy in experimental diabetes in rats

Diabetologia. 1992 Jun;35(6):589-93. doi: 10.1007/BF00400489.

Abstract

The insulin-like growth factors, insulin-like growth factor I and insulin-like growth factor II are bound to six distinct classes of insulin-like growth factor binding proteins (IGFBPs) in the circulation and in extracellular fluids. Diabetic renal hypertrophy is preceded by a transient increase in kidney insulin-like growth factor I suggestive of a renotropic function for insulin-like growth factor I. In order to examine a possible involvement of IGFBPs in initial diabetic kidney growth and in kidney insulin-like growth factor I accumulation, we studied rat kidney IGFBPs by ligand blotting during the first 4 days after induction of diabetes. Six distinct bands were identified in kidney and liver tissue with apparent molecular weight values of 38-47 (doublet), 34, 30, 24 and 20 kDa. The 38-47 kDa doublet band probably corresponds to the insulin-like growth factor binding subunit of IGFBP-3, the 24 kDa band to IGFBP-4 and the 30 kDa band to IGFBP-1 and/or IGFBP-2, as these IGFBPs in rats have similar molecular weight. In untreated diabetic rats a transient increase in the kidney 30 kDa band was demonstrable 24 h after induction of diabetes with a maximal rise (two-fold) after 48 h, followed by a decrease to baseline values after 4 days. In untreated diabetic rats the 38-47 kDa doublet band also increased (two-fold) in kidney during the first 2 days after induction of diabetes, followed by a subsequent decrease. Insulin-treatment prevented both the increase in the 30 kDa and in the 38-47 kDa bands.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blood Glucose / metabolism
  • Carrier Proteins / isolation & purification
  • Carrier Proteins / metabolism*
  • Diabetes Mellitus, Experimental / drug therapy
  • Diabetes Mellitus, Experimental / metabolism*
  • Diabetes Mellitus, Experimental / pathology
  • Electrophoresis, Polyacrylamide Gel
  • Hypertrophy
  • Insulin / therapeutic use
  • Insulin-Like Growth Factor Binding Protein 2
  • Insulin-Like Growth Factor Binding Protein 4
  • Insulin-Like Growth Factor Binding Proteins
  • Insulin-Like Growth Factor I / metabolism*
  • Kidney / drug effects
  • Kidney / metabolism*
  • Kidney / pathology
  • Liver / metabolism
  • Male
  • Molecular Weight
  • Organ Size / drug effects
  • Rats
  • Rats, Inbred Strains

Substances

  • Blood Glucose
  • Carrier Proteins
  • Insulin
  • Insulin-Like Growth Factor Binding Protein 2
  • Insulin-Like Growth Factor Binding Protein 4
  • Insulin-Like Growth Factor Binding Proteins
  • Insulin-Like Growth Factor I