INTRACELLULAR REDOX STATE AND STIMULATION OF GLUCONEOGENESIS BY GLUCAGON AND NOREPINEPHRINE IN THE PERFUSED-RAT-LIVER
INTRACELLULAR REDOX STATE AND STIMULATION OF GLUCONEOGENESIS BY GLUCAGON AND NOREPINEPHRINE IN THE PERFUSED-RAT-LIVER
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DOI：
10.1093/oxfordjournals.jbchem.a132721
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发表时间：
1980-01-01
影响因子：
2.7
通讯作者：
OSHINO, N
中科院分区：
文献类型：
--
作者：
SUGANO, T;SHIOTA, M;OSHINO, N
通过荧光测量细胞内吡啶核苷酸的氧化还原状态，在无 Hb 灌注的大鼠肝脏中研究细胞氧化还原状态在糖异生的激素刺激中的作用。当乳酸/丙酮酸比例为 10:1 时，观察到从乳酸/丙酮酸混合物产生葡萄糖的最大速率，该比例对应于体内观察到的比例。输注乙醇或辛酸时吡啶核苷酸的减少增加与丙酮酸产生的葡萄糖增加有关，而乳酸产生的葡萄糖减少。胰高血糖素对乳酸的糖异生作用受乳酸/丙酮酸比率的影响；乳酸/丙酮酸比率的降低导致胰高血糖素功效的降低。胰高血糖素对丙酮酸产生葡萄糖的刺激在辛酸输注期间被消除，尽管在乙醇输注期间仍然可以观察到。与胰高血糖素相反，去甲肾上腺素对糖异生的刺激作用不受乳酸与丙酮酸比例的影响。去甲肾上腺素在辛酸和乙醇存在下仍然诱导刺激乳酸和丙酮酸产生葡萄糖，这总是伴随着吡啶核苷酸的短暂减少。细胞质中NADH的再生是糖异生的调节因素之一，胰高血糖素和去甲肾上腺素对糖异生和吡啶核苷酸氧化还原状态的影响并不相同。
The role of the cellular redox state in the hormonal stimulation of gluconeogenesis was studied in Hb-free perfused rat liver, by fluorimetric measurement of the redox states of intracellular pyridine nucleotides. The maximum rate of glucose production from lactate/pyruvate mixture was observed with a lactate/pyruvate ratio of 10:1, which corresponds to the ratio observed in vivo. Increased reduction of pyridine nucleotides on infusion of ethanol or octanoate was associated with an increased production of glucose from pyruvate, whereas glucose production from lactate decreased. Stimulation of gluconeogenesis from lactate by glucagon was affected by the lactate/pyruvate ratio; a decrease of the lactate/pyruvate ratio resulted in a decrease of the efficacy of glucagon. Stimulation by glucagon of glucose production from pyruvate was abolished during octanoate infusion, although it was still observable during ethanol infusion. In contrast to glucagon, the stimulatory effect of norepinephrine on gluconeogenesis was unaffected by the ratio of lactate to pyruvate. Norepinephrine in the presence of octanoate and ethanol still induced stimulation of glucose production from lactate and pyruvate, which was always accompanied by a transient reduction of pyridine nucleotides. The regeneration of NADH in the cytosol is one of the regulatory factors in gluconeogenesis, and the effects of glucagon and norepinephrine on gluconeogenesis and on the redox state of pyridine nucleotides are not identical.