Fig. 1. (Top ) Effect of increasing superfusate D-glucose concentration from 5 mm to 20 mm on diameter of endothelium-intact and -denuded arterioles at intraluminal pressures of 60 and 120 mmHg and of endothelium-intact arterioles pretreated with N G-nitro-l-arginine methylester (l-NAME, 10−5m) and indomethacin (10−5m) at 60 mmHg. P < 0.05 for difference between endothelium-intact and -denuded arterioles and for difference between endothelium-intact arterioles with and without l-NAME. (Middle ) Effect of increasing superfusate D-glucose concentration to 44 mm on diameter of endothelium-intact and -denuded arterioles at an intraluminal pressure of 60 mmHg. P < 0.05 for difference between endothelium-intact and endothelium-denuded groups. (Bottom ) Effect of changing superfusate solution from physiologic saline containing 5 mm D-glucose to 5 mm D-glucose plus 15 mm L-glucose in arterioles with and without endothelium at intraluminal pressures of 60 mmHg and 120 mmHg.