ビタミンB_6の腸管吸収機構 : (I) シロネズミ反転腸管リングによる^3H-ピリドキソールの取込み

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タイトル別名
  • Mechanism of Intestinal Absorption of Vitamin B_6 : (I) THE UPTAKE OF ^3H-PYRIDOXOL BY THE EVERTED RING SEGMENTS OF RAT INTESTINE
  • ビタミンB6の腸管吸収機構-1-シロネズミ反転腸管リングによる3H-ピリドキソールの取込み
  • ビタミン B6 ノ チョウカン キュウシュウ キコウ 1 シロネズミ ハンテン チョウカン リング ニ ヨル 3H-ピリドキソール ノ トリコミ

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The uptake of ^3H-pyridoxol (^3H-POL) by rat intestinal tissues was investigated at a range of 0.1〜4μM concentrations of the vitamin by the everted intestinal ring method. On incubation at 37℃ for 5 min the intracellular concentration of the total radioactive materials was increased proportionally to the external ^3H-POL concentration. On the other hand, incubation at 37℃ for 60 min resulted in an intracellular accumulation of the radioactive materials against the concentration gradient. The ratio of intracellular to extracellular concentration of the labeled compounds was high at low external concentrations and diminished as the external concentration increased but was constantly higher than unity. By lowering the temperature of incubation to 0℃ or addition of 4-deoxypyridoxol (DOPOL) the uptake was appreciably inhibited. The inhibition by DOPOL was much more remarkable in the uptake during 60 min incubation than that during 5 min incubation. It was also found that a certain uptake could occur, independent of the inhibition, even at an infinitive deoxypyridoxol concentration. ^8H-POL taken up into the intracellular space was metabolized rapidly to pyridoxol phosphate (POLP), pyridoxal phosphate (PALP) and pyridoxamine phosphate (PAMP) to be accumulated. The addition of DOPOL led to a marked inhibition of B_6 phosphorylation and increase of free POL. From these results it is concluded that ^3H-POL enters the intracellular space physicochemically and is accumulated by the metabolic conversions to POLP, PALP and PAMP, which seem to be a concentrative accumulation.

収録刊行物

  • ビタミン

    ビタミン 47 (9-10), 453-461, 1973

    公益社団法人 日本ビタミン学会

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