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Concentration gradient of oxalate from cortex to papilla in rat kidney
Author(s) -
NAKATANI TATSUYA,
ISHII KEIICHI,
SUGIMOTO TOSHIKADO,
KAMIKAWA SADANORI,
YAMAMOTO KEISUKE,
YONEDA YUKIO,
KANAZAWA TOSHINAO,
KISHIMOTO TAKETOSHI
Publication year - 2003
Publication title -
international journal of urology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 67
eISSN - 1442-2042
pISSN - 0919-8172
DOI - 10.1046/j.1442-2042.2003.00576.x
Subject(s) - renal papilla , oxalate , major duodenal papilla , inulin , renal cortex , kidney , calcium oxalate , nephron , medicine , cortex (anatomy) , urinary system , medulla , anatomy , chemistry , biochemistry , biology , inorganic chemistry , neuroscience
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 with 14 C‐inulin.Results:The radioactivity of 14 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 of 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.