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International Journal of Experimental Diabetes Research
Volume 3 (2002), Issue 3, Pages 205-212
http://dx.doi.org/10.1080/15604280214275

Protein Tyrosine Phosphatase 1B is Impaired in Skeletal Muscle of Diabetic Psammomys Obesus

1Department of Molecular Signaling, Hagedorn Research Institute, Gentofte, Denmark
2Department of Biochemistry and Diabetes Research Unit, Hadassah University Hospital, Jerusalem 91120, Israel

Received 26 February 2002; Accepted 12 May 2002

Copyright © 2002 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Protein tyrosine phosphatases (PTPases) have been suggested to modulate the insulin receptor signal transduction pathways.We studied PTPases in Psammomys obesus, an animal model of nutritionally induced insulin resistance. No changes in the protein expression level of src homology PTPase 2 (SHP-2) (muscle, liver) or leukocyte antigen receptor (LAR) (liver) were detected. In contrast, the expression level of PTPase 1B (PTP 1B) in the skeletal muscle, but not in liver, was increased by 83% in the diabetic animals, compared with a diabetes-resistant line. However, PTP 1B– specific activity (activity/protein) significantly decreased (50% to 56%) in skeletal muscle of diabetic animals, compared with both the diabetes-resistant line and diabetes-prone animals. In addition, PTP 1B activity was inversely correlated to serum glucose level (r = –.434, P < .02). These findings suggest that PTP 1B, though overexpressed, is not involved in the susceptibility to insulin resistance in Psammomys obesus and is secondarily attenuated by hyperglycemia or other factors in the diabetic milieu.