The renal reabsorptive mechanism for inorganic phosphate in normal and acidotic dogs
The renal reabsorptive mechanism for inorganic phosphate in normal and acidotic dogs
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DOI：
10.1152/ajplegacy.1944.142.5.648
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发表时间：
1944-12-01
影响因子：
--
通讯作者：
Alexander, RS
中科院分区：
文献类型：
--
作者：
Pitts, RF;Alexander, RS
在未麻醉的狗身上研究了肾小管对无机磷酸盐的重吸收。血浆浓度范围为1-52 mg。通过持续静脉输注中性磷酸钠获得%的磷酸磷。数据表明，磷酸盐是通过一种主动机制重吸收的，这种机制表现出一定的重吸收能力限制。在所研究的4只狗中，体重为15-20 kg，该再吸收能力为3-4.5 mg。当肾小管负荷超过这个容量时，过量的磷被定量排出。最大重吸收率是在比开始排泄所需的负荷稍高的负荷下达到的，因此不存在尖锐的肾阈值。葡萄糖重吸收机制的饱和会抑制肾小管对磷酸盐的最大重吸收能力，表明这两个系统之间存在竞争。然而根皮苷，阻止葡萄糖的重吸收，是没有影响或可能略有增加磷酸盐的重吸收。这表明肾脏机制不可能完全相同。磷酸盐的重吸收能力保持不变，尽管在血浆电解质模式的相当大的变化。以CO2结合力为代表的酸碱平衡的变化范围为29 - 93体积%，对磷酸盐重吸收机制没有影响。磷酸盐排泄在纠正酸中毒状态中的重要性仅取决于其作为尿液主要缓冲成分的存在;它并不表明肾小管重吸收机制的任何特异性反应。
The renal tubular reabsorption of inorganic phosphate has been studied in unanesthetized dogs. Plasma concs. ranging from 1-52 mg. % phosphate phosphorous were attained by continuous intravenous infusion of neutral Na phosphate. The data demonstrate that phosphate is reabsorbed by an active mechanism which exhibits a definite limitation of re-absorptive capacity. In the 4 dogs studied, which weighed from 15-20 kg., this reabsorptive capacity amounted to 3-4.5 mg. of phosphate phosphorous/min. When the tubular load exceeds this capacity, the excess is excreted quantitatively. The maximal rate of reabsorption is attained at somewhat higher loads than are necessary to initiate excretion, and therefore no sharp renal threshold exists. Saturation of the glucose reabsorptive mechanism depresses the maximal capacity for tubular reabsorption of phosphate, demonstrating competition between these 2 systems. Yet phlorizin, which blocks the reabsorption of glucose, is without effect or may increase slightly the reabsorption of phosphate. This indicates that the renal mechanisms cannot be identical in their entirety. The reabsorptive capacity for phosphate remains constant in spite of considerable alterations in the plasma electrolyte pattern. Changes in acid base balance represented by CO2 combining powers ranging from 29 to 93 vol. % have no effect on the phosphate reabsorptive mechanism. The importance of phosphate excretion in correcting a state of acidosis is dependent solely on its presence as the chief buffer constituent of the urine; it is not indicative of any specific response of the tubular reabsorptive mechanism.