Siegfried B A, Valdes R
Department of Pathology, Jewish Hospital, St. Louis, MO.
Clin Chem. 1988 May;34(5):960-4.
We studied the effect of varying water and salt intake on the renal excretion of endogenous digoxin-like immunoreactive factors (DLIF). DLIF were measured in human urine and serum by competitive displacement of 125I-labeled digoxin from anti-digoxin antibodies. Diuresis was selectively induced in normal healthy humans by acute water ingestion, and natriuresis was preferentially induced by acute saline ingestion. We found the amount of endogenous immunoreactivity excreted in urine to be correlated with urine flow rate but not with urinary sodium excretion. Urinary excretion of DLIF, normalized to creatinine, was 3.6-fold greater at a urine flow rate of 5.5 mL/min than at 0.5 mL/min. On the other hand, saline intake increased urine flow rate 1.9-fold and increased sodium excretion threefold, but did not affect urinary excretion of DLIF. Fractional excretion of DLIF was linearly related to fractional excretion of water. This study demonstrates that normalization of DLIF values to urinary creatinine does not make DLIF excretion independent of urine flow rate and underscores the need for information on urine flow rate when DLIF measurements in urine are being interpreted.
我们研究了不同水盐摄入量对内源性地高辛样免疫反应因子（DLIF）肾排泄的影响。通过125I标记的地高辛与抗地高辛抗体的竞争性置换，测定人尿液和血清中的DLIF。在正常健康人中，通过急性饮水选择性诱导利尿，通过急性摄入盐水优先诱导排钠。我们发现尿液中排泄的内源性免疫反应性与尿流率相关，但与尿钠排泄无关。以肌酐标准化后，尿流率为5.5 mL/min时，DLIF的尿排泄量比0.5 mL/min时高3.6倍。另一方面，摄入盐水使尿流率增加1.9倍，钠排泄增加3倍，但不影响DLIF的尿排泄。DLIF的分数排泄与水的分数排泄呈线性相关。本研究表明，将DLIF值以尿肌酐标准化并不能使DLIF排泄独立于尿流率，并强调在解释尿中DLIF测量结果时需要尿流率信息。
