AJP - Cell Physiology, Vol 259, Issue 2 279-C285, Copyright © 1990 by American Physiological Society
Liver glucose transporter: a basolateral protein in hepatocytes and intestine and kidney cells
B. Thorens, Z. Q. Cheng, D. Brown and H. F. Lodish
Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142.
The "liver" isoform of the facilitated diffusion glucose transporter is
expressed predominantly in liver, intestine, kidney, and pancreatic islet
beta-cells. The apparent molecular mass of the transporter in liver,
kidney, and intestine is different, as detected by Western blot analysis of
membrane proteins using antipeptide antibodies. However, as assessed by
Northern blot analysis and molecular cloning, the same mRNA is expressed in
these tissues, indicating that there are tissue-specific posttranslational
modifications of the same transporter polypeptide. As determined by
immunofluorescence analysis on frozen tissue sections, the liver glucose
transporter is present on the sinusoidal membrane of hepatocytes, on the
basolateral membrane of fully differentiated absorptive intestine
epithelial cells, and on the basolateral membrane of proximal tubule cells
of the kidney nephron. This localization is consistent with the involvement
of the liver glucose transporter in several key steps of glucose
metabolism: glucose uptake and release by the liver and absorption or
reabsorption by epithelial cells of the intestine and kidney, respectively.
