Rognstad R, Katz J
J Biol Chem. 1977 Mar 25;252(6):1831-3.
Glucagon and L-epinephrine stimulate gluconeogenesis from 20 mM L-lactate, the effect being about 3 times greater in liver cells from fed rats than in those from fasted rats. The rate of pyruvate kinase flux was estimated to be less than 10% of the rate of gluconeogenesis from lactate in hepatocytes from fasted rats, and neither glucagon nor epinephrine lowered the absolute rate significantly. In hepatocytes from fed rats, however, the rate of pyruvate kinase was nearly one-half that of gluconeogenesis. Glucagon caused a marked depression of pyruvate kinase flux, with 1 muM glucagon lowering the rate to nearly the level found in cells from fasted rats Epinephrine at concentrations from 10(-8) to 10(-6) M actually increased pyruvate kinase flux during gluconeogenesis from lactate in cells from fed rats. These results are in accord with the view that the effects of glucagon and epinephrine on gluconeogenesis are not identical.
胰高血糖素和L-肾上腺素可刺激由20 mM L-乳酸生成葡萄糖的过程，该效应在喂食大鼠的肝细胞中比在禁食大鼠的肝细胞中约大3倍。据估计，在禁食大鼠的肝细胞中，丙酮酸激酶通量速率不到由乳酸生成葡萄糖过程速率的10%，胰高血糖素和肾上腺素均未显著降低其绝对速率。然而，在喂食大鼠的肝细胞中，丙酮酸激酶速率接近葡萄糖异生速率的一半。胰高血糖素使丙酮酸激酶通量显著降低，1 μM胰高血糖素可将速率降至接近禁食大鼠细胞中的水平。在喂食大鼠的细胞中，浓度为10(-8)至10(-6) M的肾上腺素实际上在由乳酸生成葡萄糖的过程中增加了丙酮酸激酶通量。这些结果与胰高血糖素和肾上腺素对葡萄糖异生的作用不同这一观点一致。
