Insulin receptor tyrosine-kinase activity is altered in both muscle and adipose tissue from non-obese normoglycaemic insulin-resistant subjects

G. Grasso, L. Frittitta, M. Anello, P. Russo, G. Sesti, V. Trischitta

Research output: Contribution to journalArticle

Abstract

We performed i. v. insulin tolerance test in 30 non-obese (BMIitt values). Then we compared the tyrosine-kinase activity of immunopurified insulin receptors (using32P-ATP and poly-glu-tyr (4∶1) from both muscle and adipose tissue in 7 of the most insulin-sensitive and 7 of the most insulin-resistant subjects. No difference was observed between the two groups in the basal (no insulin) receptor tyrosine-kinase activity from both tissues. In contrast, tyrosine-kinase activity response to insulin was significantly higher (p50 being 0.87±0.05 nmol/l vs 2.03±0.07, p50 of muscle receptor tyrosine-kinase significantly (p=0.001) correlated to both Kitt values (r=−0.79) and plasma insulin values at 120 min during OGTT (r=+0.80). Insulin receptor content, as assessed by radioimmunoassay, was similar in both muscle (7.9±1.3 and 9.2±1.9 ng/mg protein) and adipose tissue (8.2±1.3 and 7.5±1.4) of insulin-sensitive and-resistant subjects. Exon 11+ isoform of insulin receptor was similarly represented in muscle speciments from six insulin-sensitive (80±8% of total receptor content) and six resistant (78±6%) subjects. In conclusion, a defective insulin stimulation of receptor tyrosine-kinase activity is present in both muscle and adipose tissue of euglycaemic non-obese insulin-resistant subjects. This defect is, therefore, an early event in the development of insulin resistance. [Diabetologia, (1995) 38: 55–61]

Original languageEnglish
Pages (from-to)55-61
Number of pages7
JournalDiabetologia
Volume38
Issue number1
DOIs
Publication statusPublished - 1995

Keywords

  • adipose tissue
  • Insulin receptor
  • insulin resistance
  • muscle tissue
  • tyrosine-kinase

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Internal Medicine

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