A HIGH-YIELD PREPARATION OF BRUSH-BORDER MEMBRANE-VESICLES FROM ORGAN-CULTURED EMBRYONIC CHICK JEJUNUM - DEMONSTRATION OF INSULIN SENSITIVITY OF NA+-DEPENDENT D-GLUCOSE TRANSPORT

被引:6
作者
DEBIEC, H [1 ]
CROSS, HS [1 ]
PETERLIK, M [1 ]
机构
[1] UNIV VIENNA,SCH MED,DEPT GEN & EXPTL PATHOL,A-1090 VIENNA,AUSTRIA
关键词
BRUSH-BORDER MEMBRANE VESICLES; SMALL INTESTINE; D-GLUCOSE UPTAKE; INSULIN; CHICKS;
D O I
10.1093/jn/121.1.105
中图分类号
R15 [营养卫生、食品卫生]; TS201 [基础科学];
学科分类号
100403 ;
摘要
Although embryonic chick small intestinal segments provide a very limited amount of tissue for preparation of enterocyte brush border membrane vesicles (BBMV), we were able to develop a procedure for isolation of BBMV form cultured 20-d-old embryonci chick jejunum in high yield by modifying a divalent cation precipitation method. Total yield of the brush border marker enzyme alkaline phosphatase in the vesicle fraction as compared to the crude homogenate was approximately 40%, and the specific activity of the enzyme was increased 25-fold on the average. The brush border membrane vesicle fraction was only contaminated with other cellular organelles (basolateral membranes, mitochondria, lysosomes or endoplasmic reticulum) to a minor extent. Functional integrity of the brush border vesicles was indicated by Na+ gradient-driven electrogenic D-glucose transport leading to concentrative transfer (overshoot) of the sugar into an osmotically active intravesicular space. When jejuna were cultured for 48 h in the presence of 10(-6) mol/L insulin, the initial rate of Na+-dependent D-glucose uptake by brush border membrane vesicles as well as Na+-dependent [H-3]phlorizin binding to brush border membranes was approximately twice as high as in vesicles from untreated controls. This strongly suggests that insulin could enhance intestinal absorption of D-glucose by increasing the intrinsic activity of the Na+-dependent D-glucose transport system at the luminal membrane of enterocytes.
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页码:105 / 113
页数:9
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