Back to Search
Start Over
Uptake of drugs and expression of P-glycoprotein in the rat 9L glioma.
- Source :
-
Experimental brain research [Exp Brain Res] 1993; Vol. 95 (1), pp. 41-50. - Publication Year :
- 1993
-
Abstract
- Two weeks after the inoculation of 1.5 x 10(5) 9L glioma cells into the rat brain, the uptake of radiolabelled drugs into the brain and the experimental 9L glioma during the first cerebral circulation was measured with a liquid scintillation counter and analyzed by the method of Oldendorf (1970). The expression of P-glycoprotein, which is known to be associated with the efflux of drugs, was also studied, using anti-P-glycoprotein monoclonal antibody, C-219. Furthermore, the ultrastructure of brain capillaries, tumor vessels, and glioma cells was studied by conventional and immunoelectron microscopy. Sucrose (control), the transport of which through the blood-brain barrier is known to be negligible, accumulated to fivefold higher levels in the tumor than in normal brain. Ranimustine (MCNU), 5-fluorouracil (5-FU), and doxorubicin showed little accumulation in the normal brain, whereas nimustine (ACNU) showed an increased accumulation. MCNU and doxorubicin showed negligible accumulation in the glioma cells despite diffusion into the tumor interstitial space. In contrast, ACNU and 5-FU showed an increased accumulation in tumor cells. The accumulation of 5-FU in the cultured 9L glioma cells was decreased by ATP inhibitors or by low temperature. Although both brain capillary endothelial cells and glioma cell membrane were immunohistochemically positive for P-glycoprotein, the tumor vasculature showed low expression of P-glycoprotein. The endothelial cells of tumor vessels ultrastructurally showed increased fenestrations, swelling, and disrupted junctions. Accordingly, it is suggested that hydrophobic drugs such as doxorubicin, being pumped out by P-glycoprotein, do not accumulate in 9L glioma cells as do other lipophilic drugs such as ACNU, or drugs such as 5-FU, which accumulate by a carrier-mediated mechanism.
- Subjects :
- ATP Binding Cassette Transporter, Subfamily B, Member 1
Animals
Antibodies, Monoclonal
Biological Transport
Brain pathology
Brain ultrastructure
Capillaries pathology
Capillaries ultrastructure
Carrier Proteins analysis
Cerebral Cortex blood supply
Cerebral Cortex pathology
Glioma blood supply
Glioma pathology
Glioma ultrastructure
Hippocampus blood supply
Hippocampus pathology
Male
Membrane Glycoproteins analysis
Mesencephalon blood supply
Mesencephalon pathology
Microscopy, Electron
Microscopy, Immunoelectron
Rats
Rats, Inbred F344
Sucrose metabolism
Tumor Cells, Cultured
Venules pathology
Venules ultrastructure
Brain blood supply
Brain metabolism
Carrier Proteins biosynthesis
Drug Resistance
Fluorouracil metabolism
Glioma metabolism
Membrane Glycoproteins biosynthesis
Nimustine metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0014-4819
- Volume :
- 95
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Experimental brain research
- Publication Type :
- Academic Journal
- Accession number :
- 8104817
- Full Text :
- https://doi.org/10.1007/BF00229652