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正常成人肾每天滤过大约170升水和10克钙。但每天尿只有大约1.5升水和200毫克钙。正常情况下99％滤过水与98％滤过钙为肾小管所再吸收。早期鼠微穿刺研究,发现65％左右滤过出的水与钙是由肾脏表面的近曲小管所吸收,在接近亨利袢的远曲小管开始段内尚有10％左右滤出钙,远曲小管和远曲小管后的小管中能继续再吸收钙。随后在活体和离体灌注肾小管以及肾皮质膜囊标本中,用自由流动微穿刺的方法研究,进一步提供了肾单位各节段中钙再吸收机制。从Munich—Wistar鼠肾小囊直接取样显示约60％总血浆钙经肾小球毛细血管滤出。近曲小管再吸收大致是等张的,由于水被重吸收,其钙浓度接近肾小囊中的浓度。近曲小管再吸收钙的机制部分是被动的。因为水再吸收、钙可以自由通过近曲小管上皮以
Normal adult kidney filters approximately 170 liters of water and 10 grams of calcium daily. But urine is only about 1.5 liters of water and 200 mg of calcium daily. Under normal circumstances, 99% filtered water and 98% filtered calcium reabsorbed by the renal tubules. Early mouse micro-puncture study and found that about 65% of the filtered water and calcium is absorbed by the proximal tubule of the kidney surface, in the beginning of the distal convoluted tubule close to Henry 尚 there are about 10% leaching calcium, Yuanqu Tubules and distal convoluted tubules can continue to reabsorb calcium. Subsequent in vivo and ex vivo perfusion of renal tubules and renal cortical membrane samples, using free-flow micro-puncture method to further provide the nephron in each segment of the calcium reabsorption mechanism. Direct sampling from the Munich-Wistar rat kidney vesicles showed that about 60% of the total plasma calcium was filtered out of the glomerular capillaries. Proximal tubule reabsorption is generally isotonic, and as the water is reabsorbed, its calcium concentration is close to the concentration in the renal capsule. The mechanism by which proximal tubule reabsorbs calcium is partly passive. Because of water reabsorption, calcium is free to pass through the proximal tubule epithelium