腺苷降低离体大鼠肝细胞中乳酸糖异生作用的机制。
The mechanism by which adenosine decreases gluconeogenesis from lactate in isolated rat hepatocytes.
作者信息
Lavoinne A, Buc H A, Claeyssens S, Pinosa M, Matray F
机构信息
Groupe de Biochimie et de Physiopathologie Digestive et Nutritionnelle, U.E.R. Médecine et Pharmacie de Rouen, Saint Etienne du Rouvray, France.
出版信息
Biochem J. 1987 Sep 1;246(2):449-54. doi: 10.1042/bj2460449.
Incubation of hepatocytes from 24 h-starved rats in the presence of 0.5 mM-adenosine decreased gluconeogenesis from lactate, but not from alanine. The inhibition of gluconeogenesis was associated with a stimulation of ketone-body production and an inhibition of pyruvate oxidation. These metabolic changes were suppressed in the presence of iodotubercidin (an inhibitor of adenosine kinase), but were reinforced in the presence of deoxycoformycin (an inhibitor of adenosine deaminase); 2-chloroadenosine induced no change in gluconeogenesis from lactate. These data indicate that the inhibition of gluconeogenesis by adenosine probably results from its conversion into adenine nucleotides. In the presence of lactate or pyruvate, but not with alanine or asparagine, this conversion resulted in a decrease in the [ATP]/[ADP] ratio in both mitochondrial and cytosolic compartments. Adenosine decreased the Pi concentration with all gluconeogenic substrates.
在0.5 mM腺苷存在的情况下，对饥饿24小时大鼠的肝细胞进行孵育，可降低乳酸的糖异生作用，但对丙氨酸的糖异生作用无影响。糖异生作用的抑制与酮体生成的刺激和丙酮酸氧化的抑制相关。在碘结核菌素（腺苷激酶抑制剂）存在的情况下，这些代谢变化受到抑制，但在脱氧助间型霉素（腺苷脱氨酶抑制剂）存在的情况下则增强；2-氯腺苷对乳酸的糖异生作用无影响。这些数据表明，腺苷对糖异生作用的抑制可能是由于其转化为腺嘌呤核苷酸所致。在存在乳酸或丙酮酸的情况下，但不存在丙氨酸或天冬酰胺的情况下，这种转化导致线粒体和细胞质区室中[ATP]/[ADP]比值降低。腺苷可降低所有糖异生底物的无机磷酸盐浓度。
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