L-亮氨酸对克隆的胰岛β细胞株INS-1E细胞分泌胰岛素的葡萄糖依赖性研究

Glucose-Dependence of L-Leucine Inducing Insulin Secretion from the Clonal INS-1E Cell

目的：探讨L-亮氨酸对克隆的胰岛β细胞株INS-1E细胞分泌胰岛素的刺激作用及其葡萄糖依赖性。方法：INS-1E细胞经传代培养2d后．在Krebs—Ringer缓冲液中37℃培养箱预培养30min，再用含有不同浓度葡萄糖和不同浓度L-亮氨酸的改良Krebs—Ringer缓冲液培养60min。然后留取上清液进行胰岛素测定。结果：L-亮氨酸在0．1—10mmol·L^-1范围不增加16．7mmol·L^-1葡萄糖刺激的INS-1E细胞的胰岛素分泌，仅20mmol·L^-1的L-亮氨酸促进葡萄糖诱导的胰岛素分泌；10mmol·L^-1 L-亮氨酸在1．1、3．3、6．7mmol·L^-1葡萄糖存在的情况下促进INS—1E细胞的胰岛素分泌，而在11．1、16．7、25mmol·L^-1葡萄糖存在的情况下无促进胰岛素分泌的作用。结论：本研究显示在无刺激胰岛素分泌的葡萄糖浓度条件下，10mmol·L^-1 L-亮氨酸即显示了刺激INS-1E细胞分泌胰岛素的作用，在较高葡萄糖的条件下，10mmol·L^-1 L-亮氨酸的作用减弱或消失。

To explore the glucose dependence of L - leucine inducing insulin secretion of the clonal cell INS - 1E cells, INS -1E cells were incubated in the RPMI 1640 for 2 days, then the cells were incubated in the Krebs - Ringer buffer（KRB） with 0.1% BSA for 30 minutes. After preincubation, the ceils were incubated for 60 minutes in the modified KRB containing glucose and leucine according to the protocol. After the incubation the media were collected for insulin assay. L- leucine at concentrations of 0.1 -10mM did not potentiate the glucose （16.7mM） induced insulin secretion and L - leucine potentiated glucose - induced insulin secretion at 20mM ; lOmM L - leucine potentiated glucose（ 1.1 mM/3.3mM/6.7mM ） induced insulin secretion, but did not potentiate 11.1 mM / 16.7mM/25mM glucose induced insulin secretion. The present study showed that 10mM L - leueine could enhance insulin secretion of INS- 1E cells even at very low glucose, 10mM L- leucine induced insulin secretion attenuated or disappeared at higher glucose.