Renal iodide clearance in rabbits.
The purpose of the study was to compare indirect clearance methods based on plasma values and external detection of activity using small skin attached radioactivity detectors with a direct clearance method based on constant infusion and urine collection. The experiments were performed in anesthetized rabbits. The plasma iodide concentration was increased 100 times to prevent thyroid organification of radioactive iodide. [131I]iodide was infused at a constant rate and [125I]iodide was administered iv as a bolus for indirect clearance determination. The ratio between plasma values and external values 125I-activity was constant in all experiments from 15 min after administration of [125I]iodide and throughout the experiment. The results of 7 experiments in 3 rabbits showed a highly significant correlation (r = 0.98) between direct and indirect values within the range of direct clearance values obtained (0.002-0.6 ml.min-1.kg-1. The direct and indirect clearances were measured simultaneously during a 2-h period of steady state. The 95% confidence interval of the mean ratio between direct and indirect clearances was +/- 20% for plasma activity and +/- 26% for externally measured activity. It is concluded that both methods of indirect clearance determination can be applied to rabbits to estimate absolute values of the renal iodide clearance.
Department of Medicine M, Odense University Hospital, Denmark.
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Vadstrup
D000818:Animals; D005919:Glomerular Filtration Rate; D007454:Iodides / Q000097:blood / Q000493:pharmacokinetics*; D007668:Kidney / Q000378:metabolism*; D011817:Rabbits
D007454:Iodides