期刊
AMERICAN JOURNAL OF PHYSIOLOGY-GASTROINTESTINAL AND LIVER PHYSIOLOGY
卷 295, 期 1, 页码 G7-G15出版社
AMER PHYSIOLOGICAL SOC
DOI: 10.1152/ajpgi.00606.2007
关键词
regulation of intestinal absorption; Na-amino acid cotransport; epithelial transport; villus cells
资金
- NIDDK NIH HHS [DK-45062, DK-58034] Funding Source: Medline
Glutamine, the primary metabolic fuel for the mammalian small intestinal enterocytes, is primarily assimilated by Na-amino acid cotransporters. Although Na-solute cotransport has been shown to exist in the brush border membrane ( BBM) of the absorptive villus cells, the identity of Na-glutamine cotransport in rabbit small intestinal villus cells was unknown. Na-dependent glutamine uptake is present in villus BBM vesicles. An intravesicular proton gradient did not stimulate this Na- dependent glutamine uptake, whereas Li+ did not significantly suppress this uptake. These observations in concert with amino acid substitution studies suggested that Na- glutamine cotransporter in the villus cell BBM was the newly identified cotransporter B(0)AT1 ( SLC6A19). Quantitative real-time PCR identified the message for this cotransporter in villus cells. Thus a full-length cDNA of B0AT1 was cloned and expressed in MDA-MB-231 cells. This expressed cotransporter exhibited characteristics similar to those observed in villus cells from the rabbit small intestine. Antibody was generated for B0AT1 that demonstrated the presence of this cotransporter protein in the villus cell BBM. Kinetic studies defined the kinetic parameters of this cotransporter. Thus this study describes the identification, cloning, and characterization of the Na- amino acid cotransporter responsible for the assimilation of a critical amino acid by the absorptive villus cells in the mammalian small intestine.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据