Nutrient Reabsorption of Intestine in Vitro: Effects of Ethanol and Caffeine

離體小腸之養份吸收：酒精與咖啡因之作用

黃皓陽(H. Y. Hwang) ； 陳如儀(R. Y. Chen) ； 許明滿(M. M. Hsu) ； 紀越錦(Y. J. Jii) ； 樓迎統(Y. T. Lau)

《The Chinese Journal of Physiology》 32卷2期 (1989/12) Pp. 115-124

摘要

本研究旨在探討酒精與咖啡因對小腸（大白鼠空腸段）吸收葡萄糖及氨基酸之影響。因大部份文獻報告高濃度酒精之作用，我們測定8%酒精(～1.4 M)對鈉共輸送活性之影響，結果與先前之報告一致，高濃度酒精能抑制葡萄糖及其不可代謝之類似物3-OMG(3-O-methyl-glucose)吸收(30%)，而對氨基酸(leucine)吸收抑制則達60%。鈉－糖共輸送之特定抑制劑phloridzin(1mM)可減少葡萄糖及3-OMG吸收達60%，而不影響氨基酸之吸收。之後，我們比較不同濃度的酒精在同一動物空腸（分成20段）中之作用。結果顯示，高濃度酒精有抑制；但在低濃度酒精（即使高達200mM），並無一致的抑制作用。在同樣實驗中，phlordzin或是低濃度Na(上标 +)對養份吸收均有顯著抑制作用。因此，低濃度酒精對小腸吸收並無明顯著抑制作用。我們也測量咖啡因對小腸吸收3-OMG之影響。實驗顯示0.05mM咖啡因即可抑制3-OMG吸收達15%，與在0.5mM抑制程度相似；而當濃度達5mM，則抑制稍提高爲20%。咖啡因的作用與cAMP相類似。

並列摘要

Hwang, H.Y., R.Y. Chen, M.M. Hsu, Y. J. Jii, and Y.T. Lau: Nutrient reabsorption of intestine in vitro: effects of ethanol and caffeine. Chinese J. Physiol. 32(2):115-124, 1989. We studied the effect of ethanol and caffeine on the intestinal reabsorption (jejunum from SD rats) of glucose (Glu) and amino acids. Since most of the studies on the effect of ethanol utilized high concentration, we first characterized the effect of 8% (～1.4 M) ethanol on the activity of Na(superscript +) coupled nutrient transport. Consistent with previous reports, ethanol (＞ 1M) was found to inhibit the uptake rates of glucose and its non-metabolizable analogue 3-0-methyl-glucose (3-OMG) by 30%, while leucine (Leu) uptake was inhibited by 60%. Phloridzin, a specific inhibitor for Na(superscript +)-coupled sugar transport, at 1mM concentration could inhibit Glu and 3-OMG uptake by more than 60% without affecting Leu uptake. We then compared the effects of various concentrations of ethanol on about 20 intestinal segments taken from the same animal. We consistently observed transport inhibition at high concentration of ethanol but at low concentrations (up to 200mM), there was no consistent effect, while phloridzin or low-Na media (86% of Na replaced by choline) significantly reduced the rate of nutrient uptake in the same experiment. Thus, it appeared that low concentrations of ethanol had no significant effect on Na(superscript +)-coupled nutrient uptake. We also determined the effect of caffeine on intestinal 3-OMG uptake. At concentration of 0.05mM, caffeine inhibited 3-OMG uptake by about 15% (p＜0.05). The level of inhibition was not significantly different at 0.5mM, but a slightly higher level of inhibition (20%) was reached at 5mM. The action of caffeine could be mimicked by dibutyryl cAMP (1mM).

並列關鍵字

nutrient reabsorption ； jejunum ； ethanol ； caffeine