<p>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.</p> <p>Protein tyrosine phosphatases (PTPases) have been suggested
to modulate the insulin receptor signal transduction pathways.We
studied PTPases in <italic>Psammomys obesus</italic>, 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, <italic>P</italic> &lt; .02). These findings suggest that PTP 1B, though
overexpressed, is not involved in the susceptibility to insulin resistance
in <italic>Psammomys obesus</italic> and is secondarily attenuated by
hyperglycemia or other factors in the diabetic milieu.</p>
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Int J Exp Diabetes Res. 2002; 3(3):205-212