Acute effects of local hyperglycaemia on peripheral blood flow in man

To determine whether local hyperglycaemia affects peripheral blood flow in man, total forearm and skin microcirculatory blood flow were studied in healthy subjects before, during, and after a 1-h infusion of different concentrations of glucose or mannitol in the brachial artery. Mild or high forearm hyperglycaemia induced by 5% glucose infusion (approximately 10 mmol l-1 and approximately 18 mol l-1, respectively) did not induce any changes in forearm muscle or skin blood flow. However, mild forearm hyperglycaemia (approximately 8 mmol l-1), induced by 20% glucose infusion, acutely increased forearm blood flow, decreased forearm vascular resistance, but did not change skin blood flow. Twenty percent Mannitol infusion, as an osmotic control, did not result in any changes. We conclude that intra-arterial administration of 5% glucose does not acutely affect peripheral blood flow. The glucose-related effect induced by 20% infusion is probably due to marked hyperglycaemia at the catheter tip.