The utilization of some metabolic fuels has been measured in vitro in a preparation of rat jejunum to which the substrates were supplied via the perfusate flowing through the vascular bed. 2. In jejunum from 48 hr-fasted rats, the combined rates of utilization of 1 mM-acetoacetate and 2mM-D-3-hydroxybutyrate are similar to that of 7.5 mM-glucose. 3. The utilization of glucose is reduced in jejunum from animals fasted for 48 hr (45--63% reduction) and also from animals after 3--6 days of diabetes induced by streptozotocin (29% reduction). The addition of ketone bodies or of Na-oleate to the vascular perfusate does not reduce the utilization of glucose by the jejunum of either fed or 48 hr fasted rats. 4. Ketone bodies in the vascular perfusate reduce the oxidation of glucose by the jejunum of fed rats. In the jejunum of 48 hr-fasted rats, ketone bodies completely inhibit the oxidation of glucose so that all the glucose utilized by the tissue is converted to lactate. 5. The findings are discussed in relation to other work and it is concluded that substrates for the oxidative metabolism of the jejunum of fasted rats are likely to be ketone bodies, glutamine and fatty acids; at the same time the utilization of glucose is reduced and its oxidation completely abolished.
摘要
已在大鼠空肠制剂中进行体外测量，通过流经血管床的灌注液向该制剂提供底物，以此测定某些代谢燃料的利用率。2. 在禁食48小时的大鼠的空肠中，1 mM乙酰乙酸盐和2 mM D-3-羟基丁酸盐的联合利用率与7.5 mM葡萄糖的利用率相似。3. 禁食48小时的动物的空肠中葡萄糖利用率降低（降低45%-63%），链脲佐菌素诱导糖尿病3-6天后的动物的空肠中葡萄糖利用率也降低（降低29%）。向血管灌注液中添加酮体或油酸钠不会降低喂食或禁食48小时大鼠空肠对葡萄糖的利用率。4. 血管灌注液中的酮体会降低喂食大鼠空肠中葡萄糖的氧化。在禁食48小时的大鼠的空肠中，酮体完全抑制葡萄糖的氧化，因此组织利用的所有葡萄糖都转化为乳酸。5. 结合其他研究对这些发现进行了讨论，得出的结论是，禁食大鼠空肠氧化代谢的底物可能是酮体、谷氨酰胺和脂肪酸；与此同时，葡萄糖的利用率降低，其氧化完全被消除。
