Stein J, Milovic V, Lembcke B, Caspary W F
Department of Internal Medicine, Johann Wolfgang Goethe-Universität Frankfurt/M.
Z Gastroenterol. 1992 Dec;30(12):841-5.
Both putrescine and the polyamines spermidine and spermine are essential factors for growth and differentiation in all cells of higher eucaryotes. In principle, increased requirements of polyamines in mucosal cells either can be met by de novo-synthesis or by increasing the uptake from lumen (brush border membrane) or bloodstream (basolateral membrane). We therefore evaluated putrescine uptake in intestinal mucosal cells by using human brush border membrane vesicles (BBMV). Intravesicular uptake of putrescine was shown by osmoplots. This process was not saturable over a substrate range from 1 to 80 microM. Putrescine transport was also found to be independent of temperature (Q10 = 1.23). No differences in putrescine uptake rates were found in the presence or absence of Na+, and there was no evidence for any dependence of putrescine uptake from other cations. Our data indicate that putrescine uptake by human intestinal brush border membrane vesicles occurs by passive diffusion. It is concluded that a formerly described saturable and carrier mediated uptake in isolated intestinal mucosal cells from different species is probably influenced by active transport across the basolateral membranes. Therefore, further studies with isolated basolateral membranes are advocated.
腐胺以及多胺亚精胺和精胺都是高等真核生物所有细胞生长和分化的必需因子。原则上，黏膜细胞中多胺需求的增加可以通过从头合成，或者通过增加从肠腔（刷状缘膜）或血液（基底外侧膜）的摄取来满足。因此，我们通过使用人刷状缘膜囊泡（BBMV）评估了肠黏膜细胞中腐胺的摄取。通过渗透图显示了腐胺的囊泡内摄取。在1至80微摩尔的底物范围内，该过程不饱和。还发现腐胺转运与温度无关（温度系数Q10 = 1.23）。在存在或不存在Na +的情况下，腐胺摄取速率没有差异，也没有证据表明腐胺摄取依赖于其他阳离子。我们的数据表明，人肠刷状缘膜囊泡对腐胺的摄取是通过被动扩散发生的。得出的结论是，先前描述的来自不同物种的分离肠黏膜细胞中的可饱和且由载体介导的摄取可能受到跨基底外侧膜的主动转运的影响。因此，提倡对分离的基底外侧膜进行进一步研究。
