Fabregat I, Lorenzo M, Benito M
Departamento de Bioquímica y Biología Molecular, Ciudad Universitaria, Madrid, Spain.
Biochem Biophys Res Commun. 1989 Jun 30;161(3):1028-34. doi: 10.1016/0006-291x(89)91346-6.
Rat foetal hepatocytes in primary cultures were used as a model for the study of malic enzyme gene expression. Carbohydrates and glycolytic metabolites produced the precocious induction of the malic enzyme in foetal hepatocytes cultured in the absence of serum and hormones. Palmitate prevented this induction. Insulin and triiodothyronine produced a significant increase in the malic enzyme specific activity in all the conditions studied. A synergistic effect between the two hormones is observed only when high concentrations of glucose are present. Glucagon prevents partially the induction produced by insulin plus triiodothyronine. Both carbohydrate and hormonal inductions of malic enzyme activity are related to parallel increases in its expression, and are prevented by protein synthesis inhibitors.
原代培养的大鼠胎儿肝细胞被用作研究苹果酸酶基因表达的模型。碳水化合物和糖酵解代谢产物在无血清和激素培养的胎儿肝细胞中可使苹果酸酶早熟诱导。棕榈酸可阻止这种诱导。胰岛素和三碘甲状腺原氨酸在所研究的所有条件下均可使苹果酸酶比活性显著增加。仅当存在高浓度葡萄糖时，才观察到这两种激素之间的协同作用。胰高血糖素可部分阻止胰岛素加三碘甲状腺原氨酸所产生的诱导。苹果酸酶活性的碳水化合物诱导和激素诱导均与其表达的平行增加有关，并可被蛋白质合成抑制剂所阻止。
