Holness M J, Sugden M C
Department of Biochemistry, London Hospital Medical College, U.K.
Biochem J. 1990 May 15;268(1):77-81. doi: 10.1042/bj2680077.
The percentages of pyruvate dehydrogenase complex (PDH) in the active form (PDHa) in two lipogenic tissues (liver and brown adipose tissue) in the fed state were 12.0% and 13.4% respectively. After acute (0.5 h) insulin treatment, PDHa activities had increased by 77% in liver and by 234% in brown fat. Significant decreases in PDHa activities were observed in both tissues by 5 h after the removal of food. The patterns of decline in PDHa activities in the two lipogenic tissues were similar in that the major decreases in activities were observed within the first 7 h of starvation. The significant decreases in PDHa activities observed after starvation for 6 h were accompanied by decreased rates of lipogenesis. Hepatic and brown-fat PDHa activities after acute (30 min) exposure to exogenous insulin were less in 6 h-starved than in fed rats, but the absolute increases in PDHa activities over the 30 min exposure period were similar in fed and 6 h-starved rats. Increases in PDHa activities were paralleled by increases in lipid synthesis in both tissues. Re-activation of PDH in response to insulin treatment or chow re-feeding after 48 h starvation occurred more rapidly in brown adipose tissue than in liver. The results are discussed in relation to the importance of the activity of the PDH complex as a determinant of the total rate of lipogenesis during the fed-to-starved transition and after insulin challenge or re-feeding.
在进食状态下，两种脂肪生成组织（肝脏和棕色脂肪组织）中处于活性形式（PDHa）的丙酮酸脱氢酶复合物（PDH）的百分比分别为12.0%和13.4%。急性（0.5小时）胰岛素处理后，肝脏中PDHa活性增加了77%，棕色脂肪中增加了234%。禁食5小时后，在这两种组织中均观察到PDHa活性显著下降。两种脂肪生成组织中PDHa活性的下降模式相似，即在饥饿的前7小时内观察到活性大幅下降。饥饿6小时后观察到的PDHa活性显著下降伴随着脂肪生成速率的降低。急性（30分钟）暴露于外源性胰岛素后，饥饿6小时的大鼠肝脏和棕色脂肪中的PDHa活性低于进食大鼠，但在30分钟暴露期间PDHa活性的绝对增加在进食和饥饿6小时的大鼠中相似。两种组织中PDHa活性的增加与脂质合成的增加平行。饥饿48小时后，棕色脂肪组织中PDH对胰岛素处理或重新喂食的反应重新激活比肝脏中更快。本文讨论了这些结果与PDH复合物活性作为进食到饥饿转变期间以及胰岛素刺激或重新喂食后脂肪生成总速率决定因素的重要性之间的关系。
