Evidence for Facilitated Diffusion of Sugars in Rat Liver Lysosomes

1979 ◽  
Vol 7 (2) ◽  
pp. 364-365 ◽  
Author(s):  
KEVIN DOCHERTY ◽  
GERALD V. BRENCHLEY ◽  
C. NICHOLAS HALES
1983 ◽  
Vol 212 (1) ◽  
pp. 211-218 ◽  
Author(s):  
G A Maguire ◽  
K Docherty ◽  
C N Hales

Purified rat liver lysosomes (‘tritosomes’) were prepared from rats injected with Triton WR-1339. 2. The water space of tritosomes, measured by using [3H]water and [14C]sucrose, was 2.15 +/- 0.72 microliter/mg of protein (mean +/- S.E.M., n = 12). 3. Tritosomes, when compared with a crude preparation of normal lysosomes by an indirect method of study, showed sugar specificity but decreased stereospecificity of sugar uptake. 4. At 125 mM the relative rates of net uptake of D-[14C]ribose, D-[14C]- or D-[3H]glucose and 2-deoxy-D-[3H]glucose were the same as that inferred from the indirect study. 5. The entry of D-[3H]glucose into tritosomes showed concentration-dependence suggestive of saturation, with a Km of 48 +/- 18 mM (4). 6. D- and L-glucose, D-ribose, 2-deoxy-D-glucose and D-mannose competed with D-[14C]glucose or D-[14C]ribose for uptake. 7. Cytochalasin B inhibited D-[3H]glucose uptake. 8. Uptake of 1 mM-L-[14C]glucose was slower than for 1 mM-D-[14C]glucose. 9. It is concluded that a facilitated-diffusion transport system is present in purified rat liver lysosomes.


1979 ◽  
Vol 178 (2) ◽  
pp. 361-366 ◽  
Author(s):  
K Docherty ◽  
G V Brenchley ◽  
C N Hales

1. By the osmotic-protection method, the penetration of sugars through the rat liver lysosomal membranes was studied with a view of determining whether sugar uptake was by facilitated diffusion. 2. The following criteria for this type of transport were established: sugar specificity, the order of uptake being 2-deoxy-D-glucose less than D-glucose less than D-mannose less than D-galactose less than D-ribose less than 2-deoxy-D-ribose; stereospecificity, the uptake of L-glucose and L-ribose being 50% slower than their D-stereoisomers; inhibition by 1 MM-phlorrhizin and 1 M-cytochalastin B; competition between sugars for uptake, and a Q10 (rate difference over a 10 degrees C temperature range) for uptake of approx. 2.8. 3. It is proposed that sugar uptake into lysosomes from rat liver is by facilitated diffusion.


2009 ◽  
Vol 103 (2) ◽  
pp. 197-205 ◽  
Author(s):  
Hsu-Fang Chou ◽  
Kun-Hung Chuang ◽  
Yi-Shan Tsai ◽  
Yi-Ju Chen

Genistein and daidzein are known to have both beneficial and adverse effects on human health due to their many biological actions at the cellular level. Both isoflavones have been shown to inhibit GLUT-mediated glucose transport across the plasma membrane of mammalian cells. Since lysosomal membrane transport is essential for maintaining cellular homeostasis, the present study examined the effects of genistein and daidzein on glucose and sulphate transport in isolated rat liver lysosomes. Both genistein and daidzein significantly inhibited lysosomal glucose uptake. Genistein was a more potent glucose transport inhibitor than daidzein, with a half-maximum inhibitory concentration (IC50) of 45 μmol/l compared with 71 μmol/l for daidzein. Uptake kinetics of d-glucose showed a significant decrease in Vmax (control:genistein treat = 1489 (sem 91):507 (sem 76) pmol/unit of β-hexosaminidase per 15 s) without a change in Km. The presence of 50 μm-genistein in the medium also reduced glucose efflux from lysosomes preloaded with 100 mm-d-glucose. Genistein also inhibited lysosomal sulphate transport. Similar to its effects on glucose uptake kinetics, genistein treatment caused a significant decrease in sulphate uptake Vmax (control:genistein treat = 87 (sem 4):59 (sem 5) pmol/unit of β-hexosaminidase per 30 s), while the Km was not affected. The evidence provided by the present study suggests that the most likely mechanism of lysosomal glucose transport inhibition by genistein is via direct interaction between genistein and the transporter, rather than mediation by tyrosine kinase inactivation. Genistein likely has a similar mechanism of directly inhibiting sulphate transporter.


1988 ◽  
Vol 95 (4) ◽  
pp. 1088-1098 ◽  
Author(s):  
Richard B. Sewell ◽  
Susan A. Grinpukel ◽  
Alan R. Zinsmeister ◽  
Nicholas F. LaRusso

1969 ◽  
Vol 115 (5) ◽  
pp. 54P-54P ◽  
Author(s):  
D Robinson ◽  
P Willcox

FEBS Letters ◽  
1995 ◽  
Vol 369 (2-3) ◽  
pp. 217-220 ◽  
Author(s):  
Elena V. Rukavishnikova ◽  
Tatjana A. Korolenko ◽  
Toshihiro Sassa ◽  
Tatsuzo Oka ◽  
Saburou Horiuchi ◽  
...  

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