Maxild J, Møller J V, Sheikh M I
Biochim Biophys Acta. 1980 Oct 2;601(3):490-9. doi: 10.1016/0005-2736(80)90552-0.
Active accumulation of p-aminohippurate by cortex slices of rabbit kidney in vitro requires 2.5-3 h at 25 degrees C to attain a steady-state value. The uptake process can be divided into a rapid and a slow component. The slow component makes the largest contribution to the final accumulation of p-aminohippurate. Rapid uptake is dependent on oxidative metabolism, but is not affected by Na+ or ouabain. By way of contrast, Na+ is required for the slow uptake process to occur. Efflux of p-aminohippurate accumulated in the presence of Na+ is stimulated by transfer to media with a low concentration of Na+. On the other hand, there is only evidence of a stimulatory effect of Na+ on p-aminohippurate influx at medium concentrations above 30 mM. The results indicate the existence of both Na+-dependent and Na+-independent p-aminohippurate transport, respectively.
兔肾皮质切片在体外对对氨基马尿酸的主动积累在25摄氏度下需要2.5至3小时才能达到稳态值。摄取过程可分为快速和缓慢两个部分。缓慢部分对对氨基马尿酸的最终积累贡献最大。快速摄取依赖于氧化代谢,但不受Na+或哇巴因的影响。相比之下,缓慢摄取过程的发生需要Na+。将在Na+存在下积累的对氨基马尿酸转移到低浓度Na+的培养基中会刺激其流出。另一方面,只有在Na+浓度高于30 mM的中等浓度下,才有证据表明Na+对对氨基马尿酸流入有刺激作用。结果分别表明存在依赖Na+和不依赖Na+的对氨基马尿酸转运。