Hue L, Bartrons R
Biochem J. 1984 Feb 15;218(1):165-70. doi: 10.1042/bj2180165.
Hepatocytes from overnight-starved rats were incubated with 1-20 mM-fructose, -dihydroxyacetone, -glycerol, -alanine or -lactate and -pyruvate with or without 0.1 microM-glucagon. The production of glucose and lactate was measured, as was the content of fructose 2,6-bisphosphate. The concentrations of fructose (below 5 mM) and dihydroxyacetone (above 1 mM) that gave rise to an increase in fructose 2,6-bisphosphate were those at which a glucagon effect on the production of glucose and lactate could be observed. Glycerol had no effect on fructose 2,6-bisphosphate content or on production of lactate, and glucagon did not stimulate the production of glucose from this precursor. With alanine or lactate/pyruvate as substrates, glucagon stimulated glucose production whether the concentration of fructose 2,6-bisphosphate was increased or not. The extent of inactivation of pyruvate kinase by glucagon was not affected by the presence of the various gluconeogenic precursors. The role of fructose 2,6-bisphosphate in the effect of glucagon on gluconeogenesis from precursors entering the pathway at the level of triose phosphates or pyruvate is discussed.
将禁食过夜大鼠的肝细胞与1 - 20 mM的果糖、二羟基丙酮、甘油、丙氨酸、乳酸和丙酮酸一起孵育，同时加入或不加入0.1 microM的胰高血糖素。测定葡萄糖和乳酸的生成量以及果糖2,6 - 二磷酸的含量。能使果糖2,6 - 二磷酸含量增加的果糖（低于5 mM）和二羟基丙酮（高于1 mM）浓度，正是能观察到胰高血糖素对葡萄糖和乳酸生成有影响的浓度。甘油对果糖2,6 - 二磷酸含量或乳酸生成没有影响，胰高血糖素也不会刺激由该前体生成葡萄糖。以丙氨酸或乳酸/丙酮酸作为底物时，无论果糖2,6 - 二磷酸浓度是否升高，胰高血糖素都会刺激葡萄糖生成。胰高血糖素对丙酮酸激酶的失活程度不受各种糖异生前体存在的影响。本文讨论了果糖2,6 - 二磷酸在胰高血糖素对从磷酸丙糖或丙酮酸水平进入该途径的前体进行糖异生作用中的作用。
