Myocardial insulin-mediated glucose uptake and left ventricular geometry

Whole-body insulin sensitivity has been shown to be impaired in subjects wi th increased left ventricular relative wall thickness (RWT) and in hyperten sive subjects with left ventricular hypertrophy, but the relation between m yocardial insulin sensitivity and RWT or left ventricular mass index (LVMI) in normotension is not known. We measured myocardial and skeletal muscle g lucose uptake with [F-18]fluorodeoxyglucose and positron emission tomograph y during hyperinsulinemic euglycemic clamp in nine men with wide ranges of echocardiographic RWT and LVMI. The subjects: were male, 72-74 years old, n ormotensive and free from medication or history of heart disease. RWT corre lated inversely with skeletal muscle glucose uptake (r = -0.69, p = 0.04), borderline significantly directly with myocardial glucose uptake (r = 0.62, p = 0.07), and directly with the ratio between myocardial and skeletal mus cle glucose uptake (r = 0.77, p = 0.02) during hyperinsulinemic euglycemic clamp. LVMI was not related to insulin-mediated myocardial or skeletal musc le glucose uptake or the ratio between myocardial and skeletal muscle gluco se uptake. In conclusion, RWT was inversely related to insulin sensitivity in skeletal muscle and borderline significantly directly related to insulin sensitivity in the myocardium in healthy normotensive elderly men, whereas LVMI was not related to myocardial or skeletal muscle insulin sensitivity.