Impaired skeletal muscle glucose utilization under insulin action is a major defect in the etiology of type 2 diabetes. This is underscored by a new mouse model of type 2 diabetes generated by genetic disruption of one allele of glucose transporter 4 (GLUT4+/-), the insulin-responsive glucose transporter in muscle and adipose tissue. Male GLUT4+/- mice exhibited decreased GLUT4 expression and glucose uptake in muscle that accompanied impaired whole-body glucose utilization, hyperinsulinemia, hyperglycemia, and heart histopathology. To determine whether development of the diabetic phenotype in GLUT4+/- mice can be forestalled by preventing the onset of impaired muscle GLUT4 expression and glucose utilization, standard genetic crossing was performed to introduce a fast-twitch muscle-specific GLUT4 transgene--the myosin light chain (MLC) promoter-driven transgene MLC-GLUT4--into GLUT4+/- mice (MLC-GLUT4+/- mice). GLUT4 expression and 2-deoxyglucose uptake levels were normalized in fast-twitch muscles of MLC-GLUT4+/- mice. In contrast to GLUT4+/- mice, MLC-GLUT4+/- mice exhibited normal whole-body glucose utilization. In addition, development of hyperinsulinemia and hyperglycemia observed in GLUT4+/- mice was prevented in MLC-GLUT4+/- mice. The occurrence of diabetic heart histopathology in MLC-GLUT4+/- mice was reduced to control levels. Based on these results, we propose that the onset of a diabetic phenotype in GLUT4+/- mice can be avoided by preventing decreases in muscle GLUT4 expression and glucose uptake.
Prevention of insulin resistance and diabetes in mice heterozygous for GLUT4 ablation by transgenic complementation of GLUT4 in skeletal muscle.
T S Tsao, A E Stenbit, S M Factor, W Chen, L Rossetti, M J Charron; Prevention of insulin resistance and diabetes in mice heterozygous for GLUT4 ablation by transgenic complementation of GLUT4 in skeletal muscle.. Diabetes 1 April 1999; 48 (4): 775–782. https://doi.org/10.2337/diabetes.48.4.775
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