Diabetes, Vol 44, Issue 5 537-542, Copyright © 1995 by American Diabetes Association
Myocardial glucose uptake evaluated by positron emission tomography and fluorodeoxyglucose during hyperglycemic clamp in IDDM patients. Role of free fatty acid and insulin levels
LD Monti, G Lucignani, C Landoni, RM Moresco, P Piatti, I Stefani, G Pozza and F Fazio
Department of Medicine, Universita di Milano, Istituto Scientifico H. San Raffaele, Italy.
Myocardial and whole-body glucose metabolism was assessed in 19
insulin-dependent diabetes mellitus (IDDM) patients. A hyperglycemic clamp
was performed 1) in the absence of insulin at free fatty acid (FFA) levels
of 1.0 mmol/l (test 1); 2) in the absence of insulin at low FFA levels (0.1
mmol/l) by means of a lipid-lowering drug, acipimox (test 2); 3) during
insulin infusion to achieve systemic levels of 400 pmol/l and FFA levels of
0.1 mmol/l (test 3); and 4) at the insulin levels of test 3 but increasing
FFA to 1.0 mmol/l by means of heparin and intralipid infusion (test 4).
Myocardial glucose uptake was measured by positron emission tomography
(PET) and 2-[18F]fluoro-2-deoxy-D-glucose. Whole-body glucose uptake was
measured in the four conditions by the glucose infusion rate during the PET
scanning period. Myocardial glucose uptakes were 40.3 +/- 18.0, 395.5 +/-
139.6, 852.2 +/- 99.1, and 1,388.4 +/- 199.1 mumol.kg tissue-1.min-1 (mean
+/- SD) and whole-body glucose uptakes were 10.1 +/- 2.3, 10.1 +/- 3.4,
42.8 +/- 5.8, and 30.5 +/- 5.6 mumol.kg body wt-1.min-1 during tests 1, 2,
3, and 4, respectively. Thus, in IDDM patients without coronary artery
disease under the condition of hyperglycemia, an increase of myocardial
glucose uptake was obtained either by lowering of FFA levels during
hypoinsulinemia or by an increase in FFA levels during hyperinsulinemia. In
both conditions no significant changes of whole-body glucose uptake were
demonstrated.