Sodium-dependent phosphate transport in primary cultures of renal tubule cells from young and adult rats.
Sodium-dependent phosphate transport in primary cultures of renal tubule cells from young and adult rats.
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幼年和成年大鼠肾小管细胞原代培养物中钠依赖性磷酸盐转运。
DOI：
10.1002/jcp.1041430313
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发表时间：
1990
影响因子：
5.6
通讯作者：
Armbrecht,HJ
中科院分区：
文献类型：
--
作者：
Chen,ML;King,RS;Armbrecht,HJ
研究了幼龄（5 - 6周）和成年（10-12个月）大鼠肾细胞原代培养物对磷酸盐的转运。从青年和成年组中分离的肾小管细胞表现出典型的上皮形态和相似的生长速率。在1-500 μM的底物范围内，Na依赖性磷酸盐摄取可饱和，Km为5-7 μM。与年轻细胞相比，发现成年细胞中钠依赖性磷酸盐摄取减少（30%）。磷酸盐摄取的非钠依赖性组分不随年龄变化。此外，各种化合物（哇巴因、短杆菌肽、2，4-二硝基苯酚、KCN和砷酸盐）对磷酸盐摄取的抑制作用在两个年龄组中相似。动力学分析表明，Vmax（年轻细胞和成年细胞分别为4.4 ± 0.4和3.1 ± 0.2 nmol Pi/mg蛋白/10 min）显著降低，但Km未降低，导致成年组磷酸盐摄取减少。两个年龄组的磷酸盐外排无差异。当细胞在无磷酸盐培养基中预孵育24小时时，在年轻和成年细胞中，磷酸盐的摄取分别增加到其相应对照的46%和24%。成年肾细胞的磷酸盐摄取减少和对无磷酸盐培养基的适应有限可能是体内成年和老年动物中观察到的低磷酸盐血症和磷酸盐尿症的原因。
The transport of phosphate by primary cultures of renal cells from young (5‐6 weeks) and adult (10–12 months) rats was studied. Renal tubule cells isolated from young and adult groups exhibited typical epithelial morphology and similar growth rates. The Na‐dependent phosphate uptake was saturable with a Km of 5–7 μM over a substrate range of 1–500 μM. A decrease in Na‐dependent phosphate uptake in adult cells (30%) was found compared to that of young cells. The Na‐independent component of phosphate uptake did not vary with age. In addition, the inhibition of phosphate uptake by a variety of compounds (ouabain, gramicidin, 2,4‐dinitrolphenol, KCN, and arsenate) were similar in both age groups. Kinetic analysis showed that a significant reduction in Vmax (4.4 ± 0.4 vs. 3.1 ± 0.2 nmol Pi/mg protein/10 min in young and adult cells, respectively), but not Km, resulted in this decreased uptake of phosphate in adult groups. There was no difference in the efflux of phosphate from both age groups. When cells were preincubated in a phosphate‐free medium for 24 hours, the uptake of phosphate was increased to 46% and 24% of their corresponding controls in young and adult cells, respectively. The decreased phosphate uptake and limited adaptation to a phosphate‐free medium by the adult renal cells may account for the hypophosphatemia and phosphaturia seen in adult and old animals in vivo.