The effects of cyclopropane carboxylate on hepatic pyruvate metabolism.
The effects of cyclopropane carboxylate on hepatic pyruvate metabolism.
复制标题
环丙烷羧酸盐对肝脏丙酮酸代谢的影响。
DOI：
10.1016/0003-9861(85)90775-1
复制
发表时间：
1985
影响因子：
3.9
通讯作者：
Olson,MS
中科院分区：
文献类型：
--
作者：
Steinhelper,ME;Olson,MS
研究了环丙烷羧酸酯对空腹大鼠肝脏糖异生和[1-14C]标记丙酮酸和乳酸脱羧的影响。在灌注介质中高浓度的丙酮酸（小于0.5 mm），环丙烷羧酸的输注分别抑制丙酮酸脱羧和糖异生30%和40%。当丙酮酸（50 μm）或乳酸（1 mm）的生理浓度较低时，环丙烷羧酸盐的浓度引起丙酮酸脱羧的最大抑制（小于0.5 mm），不影响丙酮酸脱羧或糖异生。证据提出了快速形成的辅酶- a酯环丙烷羧酸酯在灌注的肝脏。输注l-(−)肉碱（20 mm）阻止环丙烷羧酸对丙酮酸脱羧和丙酮酸糖异生的抑制作用（小于0.5 mm）。有趣的是，在这些条件下，环丙烷羧基辅酶a的组织水平没有下降。目前的研究表明，当丙酮酸（小于0.5 mm）支持糖异生时，环丙烷羧酸盐通过目前定义不明确的介质，通过干扰丙酮酸→草酸→磷酸烯醇丙酮酸→丙酮酸循环，抑制丙酮酸脱羧和糖异生。
The effects of cyclopropane carboxylate on gluconeogenesis and pyruvate decarboxylation from [1-14C]-labeled pyruvate and lactate were investigated in perfused livers from fasted rats. With high concentrations of pyruvate (⩾0.5 mm) in the perfusion medium, infusion of cyclopropane carboxylate inhibited pyruvate decarboxylation and gluconeogenesis by 30 and 40%.respectively. With low, more physiological concentrations of pyruvate (50 μm) or with lactate (1 mm), cyclopropane carboxylate, at a concentration which elicits maximal inhibition of pyruvate decarboxylation from pyruvate (⩾0.5 mm), did not affect either pyruvate decarboxylation or gluconeogenesis. Evidence is presented for the rapid formation of the coenzyme-A ester of cyclopropane carboxylate in perfused livers. Infusion ofl-(−)carnitine (20 mm) prevented the inhibitory effects of cyclopropane carboxylate on pyruvate decarboxylation and gluconeogenesis from pyruvate (⩾0.5 mm. Interestingly, no decrease in the tissue level of cyclopropanecarboxyl-CoA occurs under these conditions. The present study suggests that cyclopropane carboxylate, through a presently ill-defined mediator, inhibits pyruvate decarboxylation and gluconeogenesis by interfering with the pyruvate → oxalacetate → phosphoenolpyruvate → pyruvate cycle when pyruvate (⩾0.5 mm) supports gluconeogenesis.