Roth K S, Goldmann D R, Segal S
Pediatr Res. 1978 Dec;12(12):1121-6. doi: 10.1203/00006450-197812000-00004.
The transport of alpha-aminoisobutyric acid and alpha-methyl-d-glucoside by isolated tubules from Sprague-Dawley rats at different stages of development follows a separate age-dependent pattern for each substrate. The effects of 6 M maleic acid on transport processes differ for amino acids and sugars and become manifest at distinct points during development. Maximum inhibition by maleic acid occurs at a time subsequent to maturity of these transport systems. In an effort to explain these transport phenomena, the uptake and metabolism of 14C-labeled maleic acid by the newborn or adult renal tubule was studied, showing significant binding by the tubule membrane, penetration of the cell by diffusion, and no conversion to 14CO2. Maleic acid has no demonstrable effect on the membrane-associated enzymes which are thought to play a role in the transport of small molecules.
来自不同发育阶段的斯普拉格-道利大鼠的离体肾小管对α-氨基异丁酸和α-甲基-D-葡萄糖苷的转运，每种底物都遵循一种独立的年龄依赖性模式。6M马来酸对转运过程的影响因氨基酸和糖类而异，并且在发育过程中的不同时间点显现出来。马来酸的最大抑制作用发生在这些转运系统成熟之后。为了解释这些转运现象，研究了新生或成年肾小管对14C标记马来酸的摄取和代谢，结果显示肾小管膜有显著结合，马来酸通过扩散进入细胞，且未转化为14CO2。马来酸对被认为在小分子转运中起作用的膜相关酶没有明显影响。
