Bryson J M, Cooney G J, Wensley V R, Phuyal J L, Hew M, Denyer G S, Caterson I D
Department of Endocrinology, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia.
Am J Physiol. 1995 Apr;268(4 Pt 1):E752-7. doi: 10.1152/ajpendo.1995.268.4.E752.
The activity of the pyruvate dehydrogenase complex (PDHC) was studied in tissues of controls and insulin-resistant fat-fed rats (FFR) both in the fed state and in overnight fasted animals after the induction of short-term changes in plasma insulin by an intravenous glucose load. Significant responses by the PDHC to the glucose challenge were seen in heart and white adipose tissue (WAT) in controls with smaller changes in brown adipose tissue (BAT) and quadriceps muscle (QM) and no change in liver. Reduced PDHC responses and lower fed values were seen in heart and BAT of FFR. The response in WAT of FFR was prolonged with no change in the PDHC response in QM. Plasma nonesterified fatty acids (NEFA) were decreased in response to the glucose load with no differences between controls and FFR. Tissue triglyceride levels were higher in liver and QM but not heart of FFR. These results show differential tissue PDHC responses to short-term changes in plasma insulin. The decreased PDHC activity in some tissues of the fat-fed animals despite the lack of change in plasma NEFA, together with the triglyceride accumulation seen in some tissues but not others, suggests that local intracellular fatty acid metabolism is important in the regulation of intracellular glucose oxidation.
在喂食状态下以及静脉注射葡萄糖负荷诱导血浆胰岛素短期变化后过夜禁食的动物中，研究了对照组和胰岛素抵抗脂肪喂养大鼠（FFR）组织中丙酮酸脱氢酶复合体（PDHC）的活性。在对照组中，心脏和白色脂肪组织（WAT）中PDHC对葡萄糖挑战有显著反应，棕色脂肪组织（BAT）和股四头肌（QM）变化较小，肝脏无变化。在FFR的心脏和BAT中，PDHC反应降低且喂食时的值较低。FFR的WAT中反应延长，QM中PDHC反应无变化。血浆非酯化脂肪酸（NEFA）对葡萄糖负荷有反应而降低，对照组和FFR之间无差异。FFR的肝脏和QM中组织甘油三酯水平较高，但心脏中不高。这些结果表明不同组织的PDHC对血浆胰岛素短期变化有不同反应。尽管血浆NEFA没有变化，但脂肪喂养动物某些组织中PDHC活性降低，以及某些组织而非其他组织中出现甘油三酯积累，表明局部细胞内脂肪酸代谢在细胞内葡萄糖氧化调节中很重要。
