Active Transport of Thiamine From Rat Small Intestine

Komai, Toru; Kawai, Kenji; Shindo, Hideyo

doi:10.3177/jnsv.20.163

Cited by 49 publications

(19 citation statements)

References 6 publications

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“…The competitive inhibition of thiamine analogues on the transport of thiamine has been reported in various biological systems (6,7,11,18,21). The present observation that hepatic thiamine uptake was significantly reduced in the presence of pyrithiamine, and, to a lesser degree, in the presence of oxythiamine (Table 1) was in complete agreement with previous reports.…”

Section: Discussionsupporting

confidence: 82%

“…Similar results were also obtained in other preparations (4,11,18). The nature of the transport system is similar to that demonstrated in the small intestine (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14), central nervous system (15)(16)(17)(18) and microorganisms (20)(21)(22)(23). The transport system for thiamine requires the presence of oxygen and is sodium dependent.…”

Section: Discussionmentioning

confidence: 61%

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Active transport of thiamine by freshly isolated rat hepatocytes.

Chen

1978

Journal of Nutritional Science and Vitaminology, J Nutr Sci Vit

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SummaryRat hepatocytes were freshly prepared from adult animals using the collagenase-perfusion technique. The hepatic transport of thiamine was studied in isolated liver cells. The process was found to be saturable with an apparent Kt of 0.31mM and a Vmax of 0.7 umoles/ml intracellular fluid/5 minutes. However, at higher substrate concentrations, the process proceeded in a linear fashion. Both pyrithiamine and oxythiamine were inhibitory on the hepatic uptake of thiamine, the latter showed much weaker activity than the former. The system required the presence of sodium ions and was sensitive to ouabain. Anaerobic condition and metabolic inhibitors, e.g., 2,4-dinitrophenol, cyanide, and iodoacetate suppressed the uptake rate of thiamine. Addition of ethanol in the incubation medium also caused significant reduction of thiamine uptake. Efflux studies indicated that a portion of intracellular thiamine is readily available for exodus. Chromatographic analyses showed that thiamine was only slightly metabolically altered during the transport process. It is suggested that thiamine is transported into isolated hepatic cells by an active, sodium-dependent process.

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Section: Discussionsupporting

confidence: 82%

Section: Discussionmentioning

confidence: 61%

Active transport of thiamine by freshly isolated rat hepatocytes.

Chen

1978

Journal of Nutritional Science and Vitaminology, J Nutr Sci Vit

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“…Recently, DUES et al (5) revealed that thiamine pyrophosphokinase of the red blood cells is not detected in the cell membrane at all but in the soluble frac tion. From this result, it is apparent that thiamine pyrophosphokinase does not play a direct role in the thiamine uptake and there exists a specific carrier, just as clarified for the rat small intestine in the previous paper (4).…”

Section: Effect Of Metabolic Inhibitors or Sulfhydryl Inhibitors On Tmentioning

confidence: 58%

Transport of Thiamine Into Red Blood Cells of the Rat

Komai

Shindo

1974

Journal of Nutritional Science and Vitaminology, J Nutr Sci Vit

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“…The lack of the specific component of thiamine transport in TRMA patients could alter considerably the cellular exchanges and absorption of thiamine and determine a state of vitamin deficiency, at least when food is the only source of thiamine intake. This condition in TRMA patients is worsened by the decreased level of TPKase, an exclusively cytoplasmic enzyme (Deus and Blum, 1970;Komai et al, 1974;Cusaro et al, 1977) that is necessary for the production of TPP, the important coenzymatic form of T which allows concentration and accumulation of the vitamin in tissues by metabolic trapping. While thiamine crosses cell membranes, thiamine phosphates do not.…”

Section: Discussionmentioning

confidence: 99%

Thiamine transport by erythrocytes and ghosts in thiamine‐responsive megaloblastic anaemia

Rindi

Casirola

Poggi

et al. 1991

J of Inher Metab Disea

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A 9-year study of thiamine metabolism and cellular transport was performed in two patients with thiamine-responsive megaloblastic anaemia associated with diabetes mellitus and sensorineural deafness, in their relatives, and in age-matched controls from the same area. The ratios between the content of thiamine and that of its phosphoesters in erythrocytes were within the normal range, whereas the absolute values of thiamine and thiamine compounds were reduced by about 40% as compared to controls. Thiamine pyrophosphokinase activity was about 30% lower than in controls. Thiamine treatment restored the levels of thiamine and thiamine compounds to normal values, whereas kinase was unaffected. Both the saturable (specific, predominant at low, less than 2 mumol/L, physiological concentrations of thiamine) and the non-saturable component of thiamine transport were investigated. Erythrocytes and ghosts from patients exhibited no saturable component, this abnormality being specific for the patients and not shared by their parents. It is concluded that the cells from thiamine-responsive megaloblastic anaemia patients contain low levels of thiamine compounds, probably due to their inability to take up and retain physiological concentrations of thiamine, as a result of the lack of the saturable, specific component of transport and reduced thiamine pyrophosphokinase.

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Active Transport of Thiamine From Rat Small Intestine

Cited by 49 publications

References 6 publications

Active transport of thiamine by freshly isolated rat hepatocytes.

Active transport of thiamine by freshly isolated rat hepatocytes.

Transport of Thiamine Into Red Blood Cells of the Rat

Thiamine transport by erythrocytes and ghosts in thiamine‐responsive megaloblastic anaemia

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