Insulin
resistance is associated with several coronary risk factors and is thought to
play a critical role for the development of coronary artery disease. Insulin
resistance has several causes, including an impaired skeletal muscle glucose
utilization rate (SMGU), reduced peripheral blood flow, and altered fatty
tissue metabolism, with SMGU being considered the most important. Nonetheless,
insulin resistance has only been estimated by the glucose disposal rate (GDR)
in previous studies. Methods: Skeletal muscle metabolic imaging with 18FDG
and positron emission tomography (PET) was undertaken to measure SMGU during
hyperinsulinemiceuglycemic clamping in 22 normotensive type-2 diabetics under
no medications (T2- DM), 17 normotensive non-diabetic hypertriglyceridemics,
22 patients with hypertension, and 12 agematched controls. Whole body insulin
resistance was assessed by the GDR during hyperinsulinemiceuglycemic insulin
clamping. Results: The SMGU and GDR were significantly reduced in T2DM (32.1 ± 16.6
μmol/min/kg and 24.3 ± 13.0 μmol/min/kg, respectively), hypertriglyceridemics
(36.5 ± 13.5 μmol/min/ kg and 22.7 ± 8.07 μmol/min/kg respectively) and patients
with hypertension (35.4 ± 26.6 μmol/min/kg and 29.0 ± 9.90 μmol/min/kg, respectively)
compared with controls (72.2 ± 44.1 μmol/min/kg and 43.0 ± 22.9 μmol/min/kg, p
< 0.01, respectively). In all groups studied, SMGU was significantly correlated
with GDR (r = 0.76, p < 0.01) and GDR (F = 13.9) was independently related
to SMGU (r = 0.81, p < 0.01). Conclusion: Insulin resistance is
significantly associated with SMGU to a similar degree among patients with T2DM, essential hypertension and hypertriglyceridemia. 18FDG PET functional imaging allows insulin resistance to be assessed.