Ontogenesis of the intestinal transport of biotin in the rat.
Ontogenesis of the intestinal transport of biotin in the rat.
复制标题
大鼠生物素肠道运输的个体发生。
DOI：
10.1016/0016-5085(88)90611-7
复制
发表时间：
1988
期刊：
影响因子：
29.4
通讯作者：
Redah,R
中科院分区：
文献类型：
--
作者：
Said,HM;Redah,R
使用外翻囊技术，在哺乳（16日龄）和断奶（24日龄）大鼠中检查了生物素肠道转运的发育方面。结果与我们以前报道的成年大鼠使用相同的肠道准备。在所有年龄组中，孵育20 min后，生物素的转运呈线性。乳鼠空肠中生物素的转运显著低于回肠（p < 0.05），但断奶鼠空肠和回肠中生物素的转运无显著差异。在成年大鼠中，空肠中的生物素转运显著高于回肠（p < 0.01）。在所有年龄组中，空肠中生物素的转运在低浓度（< 10 μM）下是饱和的，但在高浓度下是线性的。饱和过程的表观Km和Vmax从哺乳期到断奶期再到成年期逐渐增加（表观Km分别为0.63、2.49和3.37 μM; Vmax分别为18.3、44.7和124.4 pmol/g · min）。另一方面，非饱和过程的转运速率随着成熟而逐渐降低（哺乳、断奶和成年大鼠分别为143.8、111.6和87.5 pmol/g · min）。哺乳期和断奶大鼠中生物素的转运与成年大鼠相似，因为它具有Na+、能量和温度依赖性，并受到结构类似物的抑制。这些结果表明，生物素转运经历了明显的成熟变化。这些变化包括亲和性降低和转运载体活性（和/或数量）增加，不饱和过程转运速率降低和转运优先位点变化。
Developmental aspects of the intestinal transport of biotin were examined in suckling (16 day old) and weanling (24 day old) rats using the everted sac technique. The results were compared with those of adult rats previously reported by us using the same intestinal preparation. Transport of biotin was linear for 20 min of incubation in all age groups. Transport of biotin was significantly (p < 0.05) lower in the jejunum than the ileum of suckling rats but was not significantly different in the jejunum and the ileum of weanling rats. In adult rats, biotin transport was significantly (p < 0.01) higher in the jejunum than the ileum. In all age groups, transport of biotin in the jejunum was saturable at low concentrations (< 10 μM) but linear at high concentrations. The apparentKmandVmaxof the saturable process showed a progressive increase from suckling to weanling to adult rats (apparentKmof 0.63, 2.49, and 3.37 μM;Vmaxof 18.3, 44.7, and 124.4 pmol/g · min, respectively). On the other hand, the rate of transport by the nonsaturable process showed a progressive decrease with maturation (143.8, 111.6, and 87.5 pmol/g · min for suckling, weanling, and adult rats, respectively). Transport of biotin in suckling and weanling rats was similar to that of adult rats in that it was Na+-, energy-, and temperature-dependent and inhibited by structural analogues. These results demonstrate that biotin transport undergoes clear maturational changes. These changes include a decrease in the affinity and an increase in the activity (and/or the numbers) of the transport carrier, a decrease in the rate of transport by the nonsaturable process and a change in the preferential site of transport.