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Erythrocyte insulin receptor tyrosine kinase activity is increased in glyburide‐treated patients with type 2 diabetes in good glycaemic control
Author(s) -
Santos R. F.,
Nomizo R.,
Oliveira E.,
Ursich M.,
Wajchenberg B.,
Reaven G. M.,
Azhar S.
Publication year - 2000
Publication title -
diabetes, obesity and metabolism
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.445
H-Index - 128
eISSN - 1463-1326
pISSN - 1462-8902
DOI - 10.1046/j.1463-1326.2000.00091.x
Subject(s) - medicine , endocrinology , insulin , metformin , tyrosine kinase , diabetes mellitus , type 2 diabetes , insulin receptor , tyrosine , receptor , insulin resistance , chemistry , biochemistry
Summary Aim : The goal of this study was to test the hypothesis that insulin receptor tyrosine kinase activity of isolated erythrocytes would be greater in glyburide‐treated patients with type 2 diabetes in good glycaemic control (n = 13) than in untreated patients (n = 12) with significant fasting hyperglycaemia. Methods : The two groups were similar in age, sex distribution, and body mass index. By selection, glyburide‐treated patients had significantly (p < 0.001) lower (mean ± s.e.m.) fasting glucose (6.9 ± 0.4 vs. 13.9 ± 0.8 mmol/l) and HbA IC (7.4 ± 0.2 vs. 11.8 ± 0.9%) concentrations. In addition, insulin‐stimulated tyrosine kinase activity was increased in erythrocytes from glyburide ‐treated patients (p < 0.01). Results : Although insulin receptor number was similar in solubilized erythrocytes from the two groups, tyrosine kinase activity per insulin receptor was significantly (p < 0.02) greater in erythrocytes from glyburide‐treated patients with type 2 diabetes. Conclusions : These findings are quite similar to previously published data in metformin‐treated patients. As such, it is suggested that decreases in insulin receptor tyrosine kinase activity may contribute to the loss of insulin sensitivity in hyperglycaemic subjects (glucotoxicity), and that an improvement in glycaemic control, irrespective of how it is achieved, will help rectify this abnormality.