The aim of this study was to determine the mechanism of transport of (14)C-thiamine in the hearts of healthy (nonalcoholic) and chronically alcoholic guinea pigs. We used the single-pass, paired-tracer dilution method on isolated and retrogradely perfused guinea pig hearts. The maximal cellular uptake (U(max)) and total cellular uptake (U(tot)) of (14)C-thiamine were determined under control conditions and under influence of possible modifiers. We tested how the presence of unlabeled thiamine, metabolic inhibitors, or absence of sodium ions influence the transport of (14)C-thiamine. The results of our experiments show that the transport of (14)C-thiamine is specific and energy-dependent and that its properties are significantly changed under the influence of chronic alcoholism. The latter effect occurs by increase in both U(max) and U(tot), as a manifestation of a compensatory mechanism in thiamine deficiency.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1139/Y08-013 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
The compartmentation of phosphorylated thiamine derivatives in cultured neuroblastoma cells.
Biochim Biophys Acta
May 1994
Laboratory of General and Comparative Biochemistry, University of Liège, Belgium.
Thiamine transport in cultured neuroblastoma cells is mediated by a high-affinity carrier (KM = 40 nM). In contrast, the uptake of the more hydrophobic sulbutiamine (isobutyrylthiamine disulfide) is unsaturable and its initial transport rate is 20-times faster than for thiamine. In the cytoplasm, sulbutiamine is rapidly hydrolyzed and reduced to free thiamine, the overall process resulting in a rapid and concentrative thiamine accumulation.
View Article and Find Full Text PDFMechanism of thiamine transport in neuroblastoma cells. Inhibition of a high affinity carrier by sodium channel activators and dependence of thiamine uptake on membrane potential and intracellular ATP.
J Biol Chem
May 1994
Laboratory of General and Comparative Biochemistry, University of Liège, Belgium.
Nerve cells are particularly sensitive to thiamine deficiency. We studied thiamine transport in mouse neuroblastoma (Neuro 2a) cells. At low external concentration, [14C]thiamine was taken up through a saturable high affinity mechanism (Km = 35 nM).
View Article and Find Full Text PDFEffect of the fluoropyrimidines 5-fluorouracil and doxifluridine on cellular uptake of thiamin.
Anticancer Res
December 1989
Department of Neurology, Ulleval University Hospital, Oslo, Norway.
The effect of 5-fluorouracil (5-FU) and doxifluridine on cellular uptake and phosphorylation of thiamin was studied in two different cell systems. Uptake of 14C-Thiamine in human NHIK 3025 cells preincubated for 24 h with 0.05 mM 5-FU or 0.
View Article and Find Full Text PDFStudies on thiamine metabolism in thiamine-responsive megaloblastic anaemia.
Eur J Pediatr
January 1989
Department of Paediatrics, 2nd Medical School, University of Naples, Italy.
We have investigated thiamine metabolism and transport in the erythrocytes of two patients from unrelated families with thiamine responsive megaloblastic anaemia associated with diabetes mellitus and sensorineural deafness. Both patients had low concentrations of thiamine compounds in plasma and red blood cells. When erythrocytes were incubated with thiazole-[2-14C]-thiamine or [35S]-thiamine in vitro, the concentration of label within the cells was markedly reduced compared with controls.
View Article and Find Full Text PDFThe specific binding activity to [14C]thiamine was found to be located in hte plasma membrane of Saccharomyces cerevisiae. The activity was inhibited by several thiamine analogs and it was hardly detectable in the plasma membrane from a thiamine transport mutant of Saccharomyces cerevisiae. Some properties of the thiamine-binding activity of yeast plasma membrane are discussed in connection with those of the thiamine transport system.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!