Thacker S V, Nickel M, DiGirolamo M
Department of Medicine, Emory University School of Medicine, Atlanta, Georgia 30303.
Am J Physiol. 1987 Oct;253(4 Pt 1):E336-42. doi: 10.1152/ajpendo.1987.253.4.E336.
We investigated the effects of acute food deprivation on the rates of glucose metabolism and lactate production by epididymal fat cells isolated from 2- and 8-mo-old Wistar rats in one of three nutritional states: fed ad libitum, restricted to 50% of ad libitum, or fasted for 48 h. Food restriction did not affect total rates of basal glucose metabolism but significantly altered its pattern. In small fat cells from 2-mo-old rats, donor's food restriction led to decreased basal and insulin-stimulated glucose oxidation and fatty acid synthesis but led to increased lactate production, which increased from 4% of total glucose metabolized by cells from fed rats to 62% by cells from fasted rats. In large fat cells from 8-mo-old rats, donor's food restriction produced minimal changes in basal glucose metabolism and lactate production (already elevated at 37% of total) but caused insulin-stimulated lactate production to increase. These findings indicate that adipose tissue can produce significant amounts of lactate (with adipocyte enlargement and/or food deprivation) and may play an important role in extrahepatic generation of triose intermediates and in the Cori cycle.
我们研究了急性食物剥夺对从2月龄和8月龄Wistar大鼠分离的附睾脂肪细胞葡萄糖代谢率和乳酸生成率的影响，这些大鼠处于三种营养状态之一：自由采食、采食限制为自由采食量的50%或禁食48小时。食物限制不影响基础葡萄糖代谢的总速率，但显著改变了其模式。在2月龄大鼠的小脂肪细胞中，供体的食物限制导致基础和胰岛素刺激的葡萄糖氧化及脂肪酸合成减少，但导致乳酸生成增加，乳酸生成从自由采食大鼠细胞代谢的总葡萄糖的4%增加到禁食大鼠细胞的62%。在8月龄大鼠的大脂肪细胞中，供体的食物限制对基础葡萄糖代谢和乳酸生成产生的变化极小（乳酸生成已占总量的37%），但导致胰岛素刺激的乳酸生成增加。这些发现表明，脂肪组织（随着脂肪细胞增大和/或食物剥夺）可产生大量乳酸，并且可能在肝外生成丙糖中间体以及在科里循环中起重要作用。
