Borba-Murad Glaucia Regina, Mario Erica Guilhen, Bassoli Bruna Kempfer, Bazotte Roberto Barbosa, de Souza Helenir Medri
Department of Physiological Sciences, State University of Londrina, 86051-990, Londrina, PR, Brazil.
Cell Biochem Funct. 2005 Nov-Dec;23(6):405-13. doi: 10.1002/cbf.1163.
The acute effects of physiological levels of leptin (10 ng ml(-1)) and insulin (20 microU ml(-1)) on hepatic gluconeogenesis and ketogenesis were compared. Leptin or insulin alone decreased (p<0.05) the activation of hepatic glucose, L-lactate and urea production from L-alanine. However, the hepatic glucose production was not modified if leptin was combined with insulin. These results indicated that both, i.e. leptin and insulin, could promote a non-additive reduction in the rate of catabolism of L-alanine. However, in contrast with insulin (p<0.05), leptin did not inhibit the activation of hepatic glucose production from pyruvate or glycerol. On the other hand, activation of hepatic production of acetoacetate and beta-hydroxybutyrate from octanoate was not affected by leptin or insulin. Thus, our data demonstrate that the acute effect of leptin on hepatic metabolism was partially similar to insulin (activation of glucose production from L-alanine and activation of acetoacetate or beta-hydroxybutyrate production from octanoate) and partially different from insulin (activation of glucose production from pyruvate or glycerol).
比较了生理水平的瘦素（10 ng ml⁻¹）和胰岛素（20 μU ml⁻¹）对肝脏糖异生和酮体生成的急性影响。单独使用瘦素或胰岛素可降低（p<0.05）肝脏由L-丙氨酸生成葡萄糖、L-乳酸和尿素的活性。然而，当瘦素与胰岛素联合使用时，肝脏葡萄糖生成并未改变。这些结果表明，瘦素和胰岛素均可促进L-丙氨酸分解代谢速率的非累加性降低。然而，与胰岛素不同（p<0.05），瘦素并不抑制肝脏由丙酮酸或甘油生成葡萄糖的活性。另一方面，瘦素或胰岛素均不影响肝脏由辛酸生成乙酰乙酸和β-羟基丁酸的活性。因此，我们的数据表明，瘦素对肝脏代谢的急性影响部分与胰岛素相似（激活由L-丙氨酸生成葡萄糖以及激活由辛酸生成乙酰乙酸或β-羟基丁酸），部分与胰岛素不同（激活由丙酮酸或甘油生成葡萄糖）。
