Diabetologia

, Volume 39, Issue 2, pp 142–148

Decreased skeletal muscle phosphotyrosine phosphatase (PTPase) activity towards insulin receptors in insulin-resistant Zucker rats measured by delayed Europium fluorescence

  • D. Worm
  • A. Handberg
  • E. Hoppe
  • J. Vinten
  • H. Beck-Nielsen
Originals

DOI: 10.1007/BF00403956

Cite this article as:
Worm, D., Handberg, A., Hoppe, E. et al. Diabetologia (1996) 39: 142. doi:10.1007/BF00403956

Summary

In order to measure the phosphotyrosine phosphatase (PTPase) activity in small muscle biopsies, a sandwich-immunofluorescence assay was developed using the phosphorylated human insulin receptor as a substrate, a C-terminal insulin receptor antibody as catching antibody and Europium-labelled anti-phosphotyrosine as detecting antibody. Soluble and particulate muscle fractions were prepared from soleus muscle of obese, diabetic (fa/fa) Zucker rats and their lean littermates (Fa/-). In the soluble muscle fractions of the obese (fa/fa) rats PTPase activity was significantly reduced compared to control (Fa/-) rats (45.2±2.6% vs 61.3±4.7%, p<0.02). This reduction was completely prevented by 24 days of metformin treatment which decreased plasma glucose and plasma insulin levels. In particulate muscle fractions, however, no difference in PTPase activity was found among any groups of rats examined. These results show that the alterations in soluble PTPase activity in the insulin-resistant, diabetic Zucker rat vary with the abnormality in glucose homeostasis.

Key words

Insulin receptor phosphotyrosine phosphatases insulin resistance skeletal muscle Zucker rats metformin 

Abbreviations

PMSF

Phenyl methyl sulphonyl-fluoride

PTPase

phosphotyrosine phosphatase

BHK

baby hamster kidney

RCM-lysozyme

reduced, carboxyamidomethylated, and maleylated lysozyme

Hepes

4-(2-hydroxyethyl)-l-piperazine-ethane sulphonic acid

Copyright information

© Springer-Verlag 1996

Authors and Affiliations

  • D. Worm
    • 1
  • A. Handberg
    • 2
  • E. Hoppe
    • 3
  • J. Vinten
    • 2
  • H. Beck-Nielsen
    • 1
  1. 1.Diabetes Research Centre and Department of EndocrinologyOdense University HospitalOdenseDenmark
  2. 2.Department of Medical PhysiologyPanum Institute, University of CopenhagenCopenhagenDenmark
  3. 3.Abteilung für Molekulare BiologieMax Planck Institut für BiochemieMartinsriedGermany

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