Regional myocardial blood flow and glucose utilization during fasting and physiological hyperinsulinemia in humans.
We investigated the effect of insulin on total and regional myocardial blood flow (MBF) and glucose uptake (MGU) in healthy subjects (50 +/- 5 yr) by means of positron emission tomography (PET) with oxygen-15-labeled water (H(2)(15)O) and fluorine-18 labeled fluorodeoxyglucose ((18)FDG) before and during physiological hyperinsulinemia (40 mU.min(-1).m(-2)). Twelve male subjects were included in the study. During hyperinsulinemia, MBF increased from 0.91 +/- 0.28 to 1.01 +/- 0.31 ml.min(-1).g(-1) (n = 7 patients, P = 0.05; n = 112 regions, P < 0.005). Intersubject variability ranged from -3.0 to +41%. MGU increased from 0.11 +/- 0.08 (n = 5) to 0.56 +/- 0.08 micromol.min(-1).g(-1) (P < 0.0001, n = 7). MBF and insulin-mediated MGU were higher in the septum and anterior and lateral wall along short-axis regions of the heart. During hyperinsulinemia, MBF was also higher in the apex and midventricle compared with the base. MBF and MGU were positively correlated before (r = 0.66, P < 0.0001) and during hyperinsulinemia (r = 0.24, P < 0.05). These results provide evidence that insulin stimulates MBF in normal human hearts and appears to involve mainly those regions of the heart where insulin-mediated MGU is higher. Furthermore, regional distribution of insulin-stimulated MBF and MGU does not appear to be uniform across the left ventricular wall of healthy subjects.
Iozzo
Patricia
P
Medical Research Council Clinical Sciences Centre, Imperial College School of Medicine, Hammersmith Hospital, London W12 ONN, United Kingdom.
Chareonthaitawee
Panithaya
P
Di Terlizzi
Marco
M
Betteridge
D John
DJ
Ferrannini
Ele
E
Camici
Paolo G
PG
D003326:Coronary Circulation / Q000502:physiology*; D005215:Fasting / Q000502:physiology*; D019788:Fluorodeoxyglucose F18; D005947:Glucose / Q000493:pharmacokinetics*; D015309:Glucose Clamp Technique; D006801:Humans; D006946:Hyperinsulinism / Q000000981:diagnostic imaging / Q000503:physiopathology*; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism; D019275:Radiopharmaceuticals; D014055:Tomography, Emission-Computed
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D005947:Glucose