Human study subjects. Eight lean, healthy subjects without a family history of diabetes participated in the study. Age (50.0 ± 1.5 years), BMI (24.8 ± 0.5 kg/m2), fasting glucose (5.7 ± 0.2 mmol/l), fasting insulin (28.3 ± 9.2 pmol/l), and HbA1c (5.5 ± 0.1). Muscle biopsies (200–300 mg) were obtained from the vastus lateralis muscle by needle biopsy under local anesthesia. All subjects gave written informed consent, and the local ethics committee of Funen and Vejle County approved the study