scholarly journals A Fickian diffusion transport process with features of transport catalysis. Doxorubicin transport in human red blood cells.

1981 ◽  
Vol 78 (4) ◽  
pp. 349-364 ◽  
Author(s):  
M Dalmark ◽  
H H Storm

The transport of the antineoplastic drug doxorubicin (Adriamycin) in human red blood cells was investigated by measuring the net efflux from loaded cells. Previous data indicated that doxorubicin transport was a Fickian diffusion transport process of the electrically neutral molecule through the lipid domain of the cell membrane (Dalmark, 1981 [In press]). However, doxorubicin transport showed saturation kinetics and a concentration-dependent temperature dependence with nonlinear Arrhenius plots. The two phenomena were related to the doxorubicin partition coefficient between 1-octanol and a water phase. This relationship indicated that the two phenomena were caused by changes in the physiochemical properties of doxorubicin in the aqueous phase and were not caused by interaction of doxorubicin with cell membrane components. The physicochemical properties of doxorubicin varied with concentration and temperature because of the ability of doxorubicin to form polymers by self-association in aqueous solution like other planar aromatic molecules through pi-electron orbital interaction. The hypothesis is proposed that doxorubicin transport across cell membranes takes place by simple Fickian diffusion.

FEBS Letters ◽  
1992 ◽  
Vol 304 (1) ◽  
pp. 32-36 ◽  
Author(s):  
Shmuel Tuvia ◽  
Shlomo Levin ◽  
Rafi Korenstein

1990 ◽  
Vol 265 (27) ◽  
pp. 16035-16038 ◽  
Author(s):  
P Bütikofer ◽  
Z W Lin ◽  
D T Chiu ◽  
B Lubin ◽  
F A Kuypers

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ratnasekhar Ch ◽  
Guillaume Rey ◽  
Sandipan Ray ◽  
Pawan K. Jha ◽  
Paul C. Driscoll ◽  
...  

AbstractCircadian clocks coordinate mammalian behavior and physiology enabling organisms to anticipate 24-hour cycles. Transcription-translation feedback loops are thought to drive these clocks in most of mammalian cells. However, red blood cells (RBCs), which do not contain a nucleus, and cannot perform transcription or translation, nonetheless exhibit circadian redox rhythms. Here we show human RBCs display circadian regulation of glucose metabolism, which is required to sustain daily redox oscillations. We found daily rhythms of metabolite levels and flux through glycolysis and the pentose phosphate pathway (PPP). We show that inhibition of critical enzymes in either pathway abolished 24-hour rhythms in metabolic flux and redox oscillations, and determined that metabolic oscillations are necessary for redox rhythmicity. Furthermore, metabolic flux rhythms also occur in nucleated cells, and persist when the core transcriptional circadian clockwork is absent in Bmal1 knockouts. Thus, we propose that rhythmic glucose metabolism is an integral process in circadian rhythms.


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