['The heterogeneous distribution of coronary blood flow could represent regional differences in demand, or mismatching of regional O2 supply to demand, caused by regionally exhausted vasodilatation (anatomical/mechanical factors) or by regional arteriovenous diffusional O2 shunting. Regional coronary blood flow and global myocardial oxygenation and metabolism were measured during metabolic vasodilatation with glucose-insulin-potassium (GIK).', 'Variables were studied before and 30 and 60 min after start of a 30 min infusion of GIK (50% glucose, 4 ml.kg-1, 8 mM KCl, and 3 U insulin.kg-1). Regional blood flows were measured by radioactive microsphere technique and cardiac output by thermodilution. Experimental subjects were six anaesthetised mongrel dogs, weighing 20-27 kg.', 'GIK increased plasma osmolarity and lactate, decreased haemoglobin, and increased cardiac output by 67(29)% and systemic O2 supply by 32(13)%, at unchanged arterial and central venous pressures and heart rate. Coronary blood flow rose by 97(50)% and left ventricular O2 supply by 56(41)%. Although regional blood flows in small tissue samples of about 1 g in the left ventricle ranged from a factor 0.31 to 1.73 of mean flow, GIK did not change flow heterogeneity and regional flows significantly correlated in time. Left ventricular O2 uptake rose by 42(40)%, while venous PO2 increased and O2 extraction decreased. Global lactate uptake increased at unchanged extraction. Changes were reversed after GIK.'] Does metabolic vasodilatation with glucose-insulin-potassium change the heterogeneous distribution of coronary blood flow in the dog?