Thompson C I, Sparks H V, Spielman W S
Am J Physiol. 1985 Apr;248(4 Pt 2):F545-51. doi: 10.1152/ajprenal.1985.248.4.F545.
The present study was undertaken to determine the renal handling of plasma adenosine and the relative contribution of the kidney to the adenosine in the renal venous plasma and urine. Injections of radiolabeled adenosine, as a tracer of arterial adenosine, along with reference compounds (either inulin or 9-beta-D-arabinofuranosyl hypoxanthine, an analogue of adenosine that does not occupy the nucleoside carrier) were coupled with measurements of endogenous adenosine in the arterial and renal venous plasma and urine of 11 anesthetized dogs. The arterial and venous concentration of endogenous adenosine was 60 +/- 16 and 52 +/- 10 nM, respectively. Urinary adenosine concentration was 312 +/- 53 nM and the fractional excretion was 0.71 +/- 0.14. Of the radiolabeled adenosine injected into the renal artery, approximately 53 +/- 3% of the filtered tracer was recovered in the urine, and only 11 +/- 1% of the tracer was recovered in the venous plasma. These results demonstrate uptake of adenosine from both the tubular and vascular compartments, and analysis of single-injection multiple-indicator curves indicates that a substantial amount of the extracted arterial adenosine enters and remains in cells. We conclude that arterial plasma contributes significantly to adenosine excreted in the urine but only minimally to renal venous adenosine. Furthermore, any intervention that alters cellular uptake and metabolism of adenosine may lead to significant changes in extracellular adenosine.
本研究旨在确定肾脏对血浆腺苷的处理方式以及肾脏对肾静脉血浆和尿液中腺苷的相对贡献。注射放射性标记的腺苷作为动脉腺苷的示踪剂，同时注射参考化合物（菊粉或9-β-D-阿拉伯呋喃糖基次黄嘌呤，一种不占据核苷载体的腺苷类似物），并对11只麻醉犬的动脉、肾静脉血浆和尿液中的内源性腺苷进行测量。内源性腺苷的动脉和静脉浓度分别为60±16和52±10 nM。尿腺苷浓度为312±53 nM，排泄分数为0.71±0.14。注入肾动脉的放射性标记腺苷中，约53±3%的滤过示踪剂在尿液中回收，仅11±1%的示踪剂在静脉血浆中回收。这些结果表明腺苷从肾小管和血管腔室被摄取，单注射多指示剂曲线分析表明，大量提取的动脉腺苷进入并留在细胞中。我们得出结论，动脉血浆对尿液中排泄的腺苷有显著贡献，但对肾静脉腺苷的贡献极小。此外，任何改变腺苷细胞摄取和代谢的干预都可能导致细胞外腺苷的显著变化。
