Tyrosine kinase activity of brain insulin and IGF-1 receptors

William L. Lowe*, Derek LeRoith

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


Lectin-purified rat brain preparations demonstrate specific [125I]-insulin and [125I]-IGF-1 binding. Insulin-stimulable tyrosine kinase activity as mesured by exogenous substrate phosphorylation was present in brain and liver lectin purified preparations with the Δ kinase activity/B/F of brain -2.5 fold greater than that of liver. Insulin-stimulable tyrosine kinase activity was abolished in liver but decreased by only -50 percent in brain after immunodepletion with antiserum which recognizes insulin but not IGF-1 receptors. Insulin and IGF-1 dose responses for phosphorylation of the immunodepleted brain preparations suggested that the remaining tyrosine kinase activity was IGF-1 receptor mediated. Thus, functional IGF-1 receptors are present in rat brain, and the doses of insulin typically used to evaluate insulin receptor tyrosine kinase activity will stimulate IGF-1 receptor tyrosine kinase activity as well.

Original languageEnglish (US)
Pages (from-to)532-538
Number of pages7
JournalBiochemical and Biophysical Research Communications
Issue number2
StatePublished - Jan 29 1986

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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