乳酸脱氢酶A的过表达减弱了稳定的MIN-6β细胞系中葡萄糖诱导的胰岛素分泌。

Overexpression of lactate dehydrogenase A attenuates glucose-induced insulin secretion in stable MIN-6 beta-cell lines.

作者信息

Zhao C, Rutter G A

机构信息

Department of Biochemistry, School of Medical Sciences, University of Bristol, UK.

出版信息

FEBS Lett. 1998 Jul 3;430(3):213-6. doi: 10.1016/s0014-5793(98)00600-0.

DOI:10.1016/s0014-5793(98)00600-0

PMID:9688541

Abstract

Since islet beta-cells express little L-lactate dehydrogenase (LDH) activity, we have examined the effects on these cells of LDH overexpression. In mock-transfected MIN6 beta-cells, LDH activity was 38 nmol/min/mg protein, and 30 mM glucose stimulated secretion 10.4-fold. In two MIN6 cell clones stably overexpressing human LDH-A cDNA, insulin secretion was stimulated only 2.7- and 2.1-fold by high glucose. K+-stimulated insulin secretion was unaffected, and leucine stimulation enhanced, by LDH-A overexpression. LDH-A-overexpressing clones displayed unaltered activities of hexokinase, glucokinase, and malate dehydrogenase, slightly elevated plasma membrane lactate transport activity, and lowered insulin content. Low LDH activity would therefore appear important in beta-cell glucose sensing.

摘要

由于胰岛β细胞表达的L-乳酸脱氢酶（LDH）活性很低，我们研究了LDH过表达对这些细胞的影响。在mock转染的MIN6β细胞中，LDH活性为38 nmol/分钟/毫克蛋白质，30 mM葡萄糖刺激分泌增加10.4倍。在两个稳定过表达人LDH-A cDNA的MIN6细胞克隆中，高糖仅刺激胰岛素分泌增加2.7倍和2.1倍。LDH-A过表达不影响K⁺刺激的胰岛素分泌，但增强了亮氨酸刺激的胰岛素分泌。过表达LDH-A的克隆中己糖激酶、葡萄糖激酶和苹果酸脱氢酶的活性未改变，质膜乳酸转运活性略有升高，胰岛素含量降低。因此，低LDH活性似乎在β细胞葡萄糖感应中很重要。