Insulin-like growth factor-I is internalized after binding to the Type I insulin-like growth factor receptor

E. S. Geary, Ronald (Ron) Rosenfeld, A. R. Hoffman

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Receptor-mediated endocytosis may represent an important mechanism whereby peptide hormones exert their biological effects. The ability of recombinant insulin-like growth factor (IGF)-I to be internalized by cultured cells was evaluated in BRL-3A2 cells, a rat liver-derived cell line which lacks insulin receptors. Since recombinant IGF-I does not bind to the Type II IGF receptor, all specific binding of 125I-IGF-I in BRL-3A2 cells represents binding to the Type I receptor. Exposure of BRL-3A2 cells to IGF-I resulted in a rapid 50% deownregulation of Type I IGF receptors. Only one-half of these binding sites were sensitive to treatment with trypsin, a phenomenon which indicates that the peptide and its receptor were internalized after the cells were exposed to IGF-I. In conclusion, these experiments demonstrate that IGF-I can be internalized by cultured cells via the Type I IGF receptor, and suggest that IGF hormone action may be exerted by receptor-mediated endocytosis.

Original languageEnglish (US)
Pages (from-to)1-3
Number of pages3
JournalHormone and Metabolic Research
Volume21
Issue number1
StatePublished - 1989
Externally publishedYes

Fingerprint

IGF Type 1 Receptor
Insulin-Like Growth Factor I
Cells
Endocytosis
Cultured Cells
IGF Type 2 Receptor
Peptide Receptors
Peptide Hormones
Insulin Receptor
Somatomedins
Liver
Trypsin
Growth Hormone
Rats
Binding Sites
Hormones
Cell Line
Experiments

ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology

Cite this

Insulin-like growth factor-I is internalized after binding to the Type I insulin-like growth factor receptor. / Geary, E. S.; Rosenfeld, Ronald (Ron); Hoffman, A. R.

In: Hormone and Metabolic Research, Vol. 21, No. 1, 1989, p. 1-3.

Research output: Contribution to journalArticle

Geary, E. S. ; Rosenfeld, Ronald (Ron) ; Hoffman, A. R. / Insulin-like growth factor-I is internalized after binding to the Type I insulin-like growth factor receptor. In: Hormone and Metabolic Research. 1989 ; Vol. 21, No. 1. pp. 1-3.
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