1. Concentration gradient of oxalate from cortex to papilla in rat kidney.
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NAKATANI, TATSUYA, ISHII, KEIICHI, SUGIMOTO, TOSHIKADO, KAMIKAWA, SADANORI, YAMAMOTO, KEISUKE, YONEDA, YUKIO, KANAZAWA, TOSHINAO, and KISHIMOTO, TAKETOSHI
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CALCIUM oxalate ,KIDNEY physiology - Abstract
Abstract Background: The kidney eliminates the major fraction of plasma oxalate. It is well known that oxalate is freely filtered by glomeruli and secreted by the proximal tubules. However, the renal handling of oxalate in distal nephrons, which is considered as playing an important role in stone formation, remains obscure. Methods: At 15–180 min after intravenous injection of
14 C-oxalate to rats, the intrarenal localization of radioactivity was quantitatively measured by the radioluminographic method using a bioimaging analyzer. Tissue radioactivity was compared with plasma, and urinary radioactivities were measured by a liquid scintillation counter. The control study was conducted with14 C-inulin. Results: The radioactivity of C-oxalate in the papilla was 10 times greater than in the cortex and eight times greater than in the medulla 180 min after injection when almost no radioactivity was present in the urine. In contrast, the radioactivity of14 14 C-inulin was nine times less in the papilla than in the cortex at the same time. Conclusion: Oxalate remains in the renal papilla for an extended period. This accumulation of oxalate may be attributed to calcium oxalate crystal fixation along the deep nephron which is considered to be the first step of stone formation. [ABSTRACT FROM AUTHOR]- Published
- 2003
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