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首页> 外文学位 >THE DEVELOPMENT OF THE GLUCOSE, MYO-INOSITOL, GLUTAMIC ACID, CHOLINE AND BETA-ALANINE TRANSPORT SYSTEMS IN THE CHICK SMALL INTESTINE.
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THE DEVELOPMENT OF THE GLUCOSE, MYO-INOSITOL, GLUTAMIC ACID, CHOLINE AND BETA-ALANINE TRANSPORT SYSTEMS IN THE CHICK SMALL INTESTINE.

机译：在小肠中葡萄糖，肌肌醇，谷氨酸，胆碱和β-丙氨酸运输系统的发展。

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摘要

Hexose (D-glucose and 3-O-methyl-D-glucose), myo-inositol, glutamic acid, choline, and (beta)-alanine transports were characterized in jejunal slices and brush-border membrane (BBM) vesicles from chicks of varying ages (range: 3 days before hatch to 21 days after hatch). With slices, mediated transport activities of 3-O-methyl-D-glucose, myo-inositol and (beta)-alanine were low before hatch. These activities were found to increase at the time of hatch, reaching maximal levels 2-7 days after hatch for 3-O-methyl-D-glucose, and 3-5 days after hatch for (beta)-alanine; activities declined to adult levels over the next 2 wk. Transport activity of myo-inositol increased during the same time period. For the glutamic acid transport system, mediated transport was higher in 2 d slices than in 21 d slices, whereas mediated transport of choline remained the same during this developmental period. For the hexose transport system, the apparent Kt for phloridzin-sensitive transport (mediated route) was the same in slices from 2-day (peak transport rates) and 21-day (minimal posthatch rates) chicks; the apparent Vmax was 2.5 times greater in 2-day slices.; The apparent diffusion coefficients (Kd) for (alpha)-methylglucoside-, aspartic acid-, hemicholinium- and proline-insensitive transport of myo-inositol, glutamic acid, choline and (beta)-alanine, respectively, were the same in slices from 2- and 21-day chicks. In contrast, the Kd for phloridzin-insensitive transport of 3-O-methyl-D-glucose was 70% greater in 2-day slices than in 21-day slices.; With BBM vesicles, Na-dependent transport rates of D-glucose, glutamic acid and (beta)-alanine were greater in 2-day vesicles than in 21-day vesicles, whereas Na-dependent transport rates of myo-inositol were greater in 21-day vesicles than in 2-day vesicles. Transport rates of choline were the same in 2-day and 21-day vesicles. As in slice experiments, Kt values for phloridzin-sensitive transport of D-glucose were the same in the two preparations, but Vmax values were 1.4 times higher in the 2-day preparation.; Chick jejunal slices that were exposed to HgCl(,2) exhibited markedly reduced uptakes of D-glucose. The carrier-mediated, but not diffusive, component of uptake was affected by Hg. Within each age group, I(,50) values (concentration of HgCl(,2) causing 50% inhibition of mediated transport) for slices (mucosal plus serosal exposure) and sacs (mucosal exposure only) were nearly identical: values for BBM vesicles were slightly lower (increased sensitivity). For each preparation, I(,50) values for 2-day chicks were consistently lower than corresponding values for 21-day chicks.; Data from biochemical experiments with 2-day and 21-day BBM preparations indicate the following: (a) the total lipid, lipid phosphorus and cholesterol contents per mg membrane protein were higher in the 2-day preparation, (b) the cholesterol-to-phospholipid mole ratio was higher in the 21-day preparation, and (c) the total fatty acid content per mg membrane protein was higher in the 2-day preparation.; Taken together, these data indicate the following: (a) changes in the chick intestinal BBM are responsible for the observed changes in substrate transport by jejunal slices during development, (b) that the transport systems have different developmental timetables, (c) that changes in transport activity during development may be partly due to changes in the membrane fluidity of the BBM, and (d) that the jejunal BBM is a site of HgCl action and that membrane sites in tissue from 2-day chicks are more sensitive to Hg than similar sites in tissue from 21-day chicks.
机译：从空腹鸡的空肠切片和刷状边界膜（BBM）囊泡中表征了己糖（D-葡萄糖和3-O-甲基-D-葡萄糖），肌醇，谷氨酸，胆碱和β-丙氨酸的转运。不同的年龄（范围：孵化前3天到孵化后21天）。切片后，孵化前3-O-甲基-D-葡萄糖，肌醇和β-丙氨酸的介导转运活性较低。发现这些活性在孵化时增加，在孵化后2-O-甲基-D-葡萄糖达到2-7天达到最高水平，而在孵化后β-丙氨酸达到3-5天达到最高水平。在接下来的2周内，活动下降到成人水平。肌醇的运输活性在同一时期增加。对于谷氨酸转运系统，在2 d切片中介导的转运高于21 d切片，而在此发育时期，胆碱的介导转运保持不变。对于己糖转运系统，在2天（峰值转运率）和21天（最低孵化率）雏鸡的切片中，对phloridzin敏感转运（介导的途径）的表观Kt相同。在2天的切片中，表观Vmax增大了2.5倍。肌醇，谷氨酸，胆碱和β-丙氨酸的α-甲基葡糖苷，天冬氨酸，hemicholinium和脯氨酸不敏感转运的表观扩散系数（Kd）在相同的切片中均相同2天和21天小鸡。相比之下，在2天的切片中，Phloridzin不敏感的3-O-甲基-D-葡萄糖转运的Kd比21天的切片高70％。对于BBM囊泡，在2天的囊泡中，D葡萄糖，谷氨酸和β-丙氨酸的Na依赖性转运速率要比21天的囊泡更高，而在21天的肌醇中，Na依赖性转运速率则更高。天囊泡比2天囊泡。胆碱在2天和21天囊泡中的转运速率相同。如在切片实验中一样，两种制剂中对氯吡嗪敏感的D-葡萄糖转运的Kt值相同，但2天制剂中的Vmax值高1.4倍。暴露于HgCl（，2）的小鸡空肠切片显示D-葡萄糖的摄取显着降低。汞影响了载体介导但不是扩散的摄取成分。在每个年龄组中，切片（粘膜和浆膜暴露）和囊（仅粘膜暴露）的I（，50）值（引起介导转运抑制50％的HgCl（，2）浓度）几乎相同：BBM囊泡的值略低（灵敏度增加）。对于每种制剂，2天雏鸡的I（，50）值始终低于21天雏鸡的相应值。使用2天和21天BBM制剂的生化实验数据表明：（a）2天制剂中每毫克膜蛋白的总脂质，脂质磷和胆固醇含量更高，（b）胆固醇-在21天的制剂中-磷脂的摩尔比更高，（c）在2天的制剂中每mg膜蛋白的总脂肪酸含量更高。综上所述，这些数据表明：（a）雏鸡肠道BBM的变化与发育过程中空肠切片的底物转运观察到的变化有关，（b）转运系统具有不同的发育时间表，（c）变动发育过程中运输活动的变化可能部分是由于BBM膜流动性的变化所致；（d）空肠BBM是HgCl作用的位点，而两日龄雏鸡组织中的膜位点对Hg的敏感性高于21天小鸡的组织中的类似部位。

著录项

  • 作者

    SHEHATA, AHMED TAHIR.;

  • 作者单位

    The University of Maine.;

  • 授予单位 The University of Maine.;
  • 学科 Agriculture Animal Culture and Nutrition.; Biology Animal Physiology.
  • 学位 Ph.D.
  • 年度 1981
  • 页码 277 p.
  • 总页数 277
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 饲料;生理学;
  • 关键词

  • 入库时间 2022-08-17 11:51:32

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