부산대학교 도서관

1. l-Glutamate and glutamine have been suggested to have cardioprotective effects. However, the issue is controversial and the metabolic mechanisms underlying a beneficial effect are not well understood. 2. In the present study we investigated the effects ofl-glutamate and glutamine on haemodynamic recovery, the rate of de novo glycogen synthesis and myocardial glucose uptake during postischaemic reperfusion. 3 . Hearts from male Wistar rats (250–300 g) were divided into three groups as follows: (i) control ( n = 12); (ii)l-glutamate ( n = 12); and (iii) glutamine ( n = 12). Hearts were mounted in a Langendorff preparation and perfused with oxygenated Krebs’–Henseleit solution at 80 mmHg and 37C. Global ischaemia for 20 min was followed by 15 min reperfusion, during whichl-glutamate (50 mmol/L) or glutamine (20 mmol/L) were administered. Left ventricular developed pressure (LVDP), de novo synthesis of glycogen using [14C]-glucose and myocardial glucose uptake usingd-[2-3H]-glucose were measured. 4. l-Glutamate and glutamine increased postischaemic LVDP ( P < 0.01 vs control hearts for both).l-Glutamate and glutamine increased de novo glycogen synthesis by 78% ( P < 0.001) and 55% ( P < 0.01), respectively. At the end of reperfusion, total myocardial glycogen content was increased by bothl-glutamate and glutamine (5.7 ± 0.3 and 6.2 ± 0.7 mmol/g wet weight, respectively; P < 0.05 and 0.01, respectively) compared with that in control hearts (3.6 ± 0.4 mmol/g wet weight). Neitherl-glutamate nor glutamine affected myocardial glucose uptake during reperfusion. 5 . Improved postischaemic haemodynamic recovery afterl-glutamate and glutamine supplementation during reperfusion is associated with increased de novo glycogen synthesis, suggesting a favourable modulation of intracellular myocardial carbohydrate metabolism. [ABSTRACT FROM AUTHOR]