Namnum P, Insogna K, Baggish D, Hayslett J P
Am J Physiol. 1983 Jun;244(6):F719-23. doi: 10.1152/ajprenal.1983.244.6.F719.
Although the clearance of endogenous creatinine is used in many physiologic and metabolic studies in the rat as an index of glomerular filtration rate, there is no evidence that creatinine is a reliable test substance. Studies were therefore performed in anesthetized and conscious rats to determine the creatinine-to-inulin clearance ratio (CCr/CIn). In anesthetized animals the CCr/CIn ratio was 0.5 and in conscious rats it was 0.7 at normal basal plasma creatinine levels. After an increase in plasma creatinine to 1.9 mg/dl induced by the intravenous infusion of creatinine, the CCr/CIn ratio was 1.2. Accordingly, these data indicate that net creatinine transport across the renal tubule is bidirectional and that transport is influenced by the plasma creatinine level. At normal plasma levels creatinine is extensively reabsorbed along the nephron, whereas net secretion is associated with elevated plasma creatinine. The results demonstrate that creatinine is not a reliable marker of glomerular filtration rate in the rat.
尽管在大鼠的许多生理和代谢研究中，内源性肌酐清除率被用作肾小球滤过率的指标，但没有证据表明肌酐是一种可靠的测试物质。因此，我们在麻醉和清醒的大鼠身上进行了研究，以确定肌酐与菊粉清除率之比（CCr/CIn）。在麻醉动物中，正常基础血浆肌酐水平下CCr/CIn比值为0.5，在清醒大鼠中为0.7。静脉输注肌酐使血浆肌酐升高至1.9mg/dl后，CCr/CIn比值为1.2。因此，这些数据表明，肌酐在肾小管中的净转运是双向的，并且转运受血浆肌酐水平的影响。在正常血浆水平下，肌酐在整个肾单位中被大量重吸收，而净分泌与血浆肌酐升高有关。结果表明，肌酐不是大鼠肾小球滤过率的可靠标志物。
