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Comparisons of P ‐glycoprotein expression in isolated rat brain microvessels and in primary cultures of endothelial cells derived from microvasculature of rat brain, epididymal fat pad and from aorta
Author(s) -
Barrand M.A.,
Robertson K.J.,
von Weikersthal S.F.
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)01104-m
Subject(s) - glycoprotein , microbiology and biotechnology , aorta , biology , endothelial stem cell , pathology , anatomy , chemistry , medicine , in vitro , biochemistry
In vivo expression of P ‐glycoprotein in isolated rat brain microvessels is compared with that in vitro in primary cultures of brain endothelial cells. More P ‐glycoprotein is detected by Western immunoblotting in microvessels than in cultured endothelium. RT‐PCR with isoform‐specific primers and immunoblotting with a mdr1b‐specific antibody reveals only mdr1a in vivo but both mdr1a and mdr1b in vitro. Thus mdr1a decreases whereas mdr1b increases during culture. P ‐Glycoprotein activity is evident in vitro, with resistance modulators, e.g. verapamil, producing increases in intracellular [ 3 H]vincristine accumulation. Endothelial cells cultured from epididymal fat pad microvasculature and aorta contain little or no P ‐glycoprotein. Here, resistance modulators are less effective.