L-亮氨酸和甘氨酰肌氨酸进入正常和蛋白质营养不良幼鼠空肠的摄取动力学。

Kinetics of uptake of L-leucine and glycylsarcosine into normal and protein malnourished young rat jejunum.

作者信息

Miller P M, Burston D, Brueton M J, Matthews D M

出版信息

Pediatr Res. 1984 Jun;18(6):504-8. doi: 10.1203/00006450-198406000-00003.

DOI:10.1203/00006450-198406000-00003

Abstract

The impact of malnutrition on peptide and amino acid absorption has been studied in the immediate postweaning period. At this time peptide uptake is quantitatively more important than amino acid uptake and the vulnerability of the infant to malnutrition is great. Everted rings of rat jejunum were used to investigate the uptake of the peptide glycylsarcosine (Gly-Sar) and the amino acid L-leucine. The animals had been weaned on to isocaloric diets containing 18% or 4% protein. The rats deprived of protein at this age showed a marked growth disturbance with considerable reduction in gut length in addition to poor weight gain. Mediated influx of Gly-Sar and leucine per centimeter of jejunum was reduced in the malnourished animals: Vmax, 77 +/- 7.1 (SEM) and 65 +/- 3.6 compared with 85 +/- 10.6 and 77 +/- 4.4 nmol . min-1 . cm-1., respectively. But, when expressed in relation to body weight, the maximal transport capacity showed a marked increase with malnutrition, values being 126 and 111 nmol-1 . cm-1 . 100 g-1 body weight compared with 39 and 35 nmol-1 . cm-1 . 100 g-1 body weight for Gly-Sar and leucine respectively.

摘要

营养不良对肽和氨基酸吸收的影响已在断奶后即刻阶段进行了研究。此时，肽的摄取在数量上比氨基酸的摄取更为重要，而且婴儿极易受到营养不良的影响。采用大鼠空肠外翻环来研究肽甘氨酰肌氨酸（Gly-Sar）和氨基酸L-亮氨酸的摄取。这些动物已断奶并喂食含18%或4%蛋白质的等热量饮食。在这个年龄段缺乏蛋白质的大鼠除体重增加不佳外，还表现出明显的生长障碍，肠道长度显著缩短。营养不良的动物每厘米空肠中Gly-Sar和亮氨酸的介导内流减少：最大反应速度（Vmax）分别为77±7.1（标准误）和65±3.6，而对照组分别为85±10.6和77±4.4 nmol·min⁻¹·cm⁻¹。但是，当以体重为参照进行表达时，最大转运能力在营养不良时显著增加，Gly-Sar和亮氨酸的值分别为126和111 nmol⁻¹·cm⁻¹·100 g⁻¹体重，而对照组分别为39和35 nmol⁻¹·cm⁻¹·100 g⁻¹体重。