Montessuit C, Papageorgiou I, Tardy I, Lerch R
Department of Internal Medicine, University Hospital, Geneva, Switzerland.
Am J Physiol. 1996 Nov;271(5 Pt 2):H2060-70. doi: 10.1152/ajpheart.1996.271.5.H2060.
The pattern of substrate utilization may influence postischemic myocardial injury. To characterize the effect of nutritional state on substrate selection and contractile function during control conditions and postischemic reperfusion, hearts from fed and fasted rats were perfused retrogradely with 0.4 mM palmitate, 8 mM glucose, and 175 mU/l insulin. Under control conditions, hearts from fasted rats exhibited lower glucose oxidation (-59%) and higher palmitate oxidation (+191%) than hearts from fed rats. During reperfusion, postischemic hearts exhibited stimulation of glucose-oxidation, with no difference between hearts from fasted and fed rats. However, oxidation of palmitate remained higher after fasting (+68%). Hearts from fasted rats exhibited lower left ventricular diastolic pressure and higher left ventricular systolic pressure development during reperfusion. The results indicate that 1) substrate selection in myocardium is influenced by the nutritional state independently of substrate availability, 2) during postischemic reperfusion, inhibition of glucose oxidation is removed in hearts from fasted rats, whereas inhibition of fatty acid oxidation in hearts from fed rats is maintained, and 3) myocardial injury is lower after fasting.
底物利用模式可能影响缺血后心肌损伤。为了表征营养状态对对照条件下及缺血后再灌注期间底物选择和收缩功能的影响，用0.4 mM棕榈酸、8 mM葡萄糖和175 mU/l胰岛素对喂食和禁食大鼠的心脏进行逆行灌注。在对照条件下，禁食大鼠的心脏与喂食大鼠的心脏相比，葡萄糖氧化较低（-59%），棕榈酸氧化较高（+191%）。在再灌注期间，缺血后心脏表现出葡萄糖氧化的刺激，禁食和喂食大鼠的心脏之间无差异。然而，禁食后棕榈酸氧化仍较高（+68%）。禁食大鼠的心脏在再灌注期间表现出较低的左心室舒张压和较高的左心室收缩压发展。结果表明：1）心肌中的底物选择受营养状态影响，与底物可用性无关；2）在缺血后再灌注期间，禁食大鼠心脏中葡萄糖氧化的抑制被消除，而喂食大鼠心脏中脂肪酸氧化的抑制得以维持；3）禁食后心肌损伤较低。
