Paulson D J, Crass M F
Am J Physiol. 1982 Jun;242(6):H1084-94. doi: 10.1152/ajpheart.1982.242.6.H1084.
The metabolism of endogenous triacylglycerols (TG) was studied in perfused working hearts of control and 12-day-old streptozotocin-treated diabetic rats. TG synthesis was assessed by the incorporation of exogenous [9,10(-3)H]palmitate. TG lipolysis was assessed by the following two methods: 1) measurement of the decrease in [14C]TG after prior in vivo isotopic prelabeling with [1-14C]palmitate and 2) calculation of the change in TG content as TG synthesis minus TG lipolysis. Control and diabetic hearts were perfused with buffer containing substrate concentrations characteristic of the in vivo state [normal: 9 mM glucose, 0.5 mM free fatty acid (FFA); diabetic: 27 mM glucose, 1.2 mM FFA]. Diabetic hearts were also perfused under normal substrate conditions. In diabetic hearts perfused under diabetic conditions elevated TG levels were maintained, lipolysis was reduced or unchanged (depending on the method of determination), and synthesis was enhanced. Oxidation of TG fatty acids (TGFA) was not impaired. Control hearts showed net lipolysis coupled with lower rates of exogenous FFA uptake and TG synthesis. In diabetic hearts perfused under normal substrate conditions lipolysis and TGFA oxidation were markedly enhanced. Thus we suggest that the basis of TG accumulation seen in the diabetic heart is due to both inhibition of lipolysis and enhancement of synthesis resulting from high levels of exogenous FFA and glucose.
在对照大鼠和经链脲佐菌素处理12天的糖尿病大鼠的灌注工作心脏中，对内源性三酰甘油（TG）的代谢进行了研究。通过掺入外源性[9,10(-3)H]棕榈酸来评估TG合成。通过以下两种方法评估TG脂解：1）在用[1-14C]棕榈酸进行体内同位素预标记后，测量[14C]TG的减少；2）计算TG含量的变化，即TG合成减去TG脂解。用含有体内状态特征底物浓度的缓冲液灌注对照心脏和糖尿病心脏[正常：9 mM葡萄糖，0.5 mM游离脂肪酸（FFA）；糖尿病：27 mM葡萄糖，1.2 mM FFA]。糖尿病心脏也在正常底物条件下进行灌注。在糖尿病条件下灌注的糖尿病心脏中，TG水平维持升高，脂解降低或不变（取决于测定方法），并且合成增强。TG脂肪酸（TGFA）的氧化未受损。对照心脏显示净脂解，同时外源性FFA摄取和TG合成速率较低。在正常底物条件下灌注的糖尿病心脏中，脂解和TGFA氧化明显增强。因此，我们认为糖尿病心脏中所见TG积累的基础是由于高水平的外源性FFA和葡萄糖导致脂解抑制和合成增强。
