Details

Autor(en) / Beteiligte

• Ido, Yasuo
• Tilton, Ronald G.
• Chang, Katherine
• Pugliese, Giuseppe
• Williamson, Joseph R.

Titel

Rapid measurement of glomerular filtration rate in small animals

Ist Teil von

• Kidney international, 1992-02, Vol.41 (2), p.435-439

Ort / Verlag

New York, NY: Elsevier Inc

Erscheinungsjahr

1992

Quelle

MEDLINE

Beschreibungen/Notizen

• The conventional inulin clearance method for estimating GFR in experimental animals requires extensive surgery as well as continuous intravenous infusion of fluids and maintenance of body temperature, arterial hematocrit, and blood pressure during the collection of multiple urine samples over a prolonged time period. To obviate these problems, a number of single bolus tracer-injection techniques have been developed for estimating GFR [1–5]. These methods are based on several assumptions, including rapid distribution of tracer [1], a two-compartment tracer distribution [2, 3], and identical tracer distribution volumes in different animals [4]; any one or more of these assumptions may not be valid in pathophysiological conditions such as expanded extracellular fluid volume [5], diabetes [6], etc. The frequent blood sampling necessary to obtain reliable curve fitting [1–3, 5] is a particular problem for measuring GFR by these methods in small animals. Conventional inulin clearance (which requires relatively long urine collection times) and single-injection techniques (which require frequent blood sampling) may be especially difficult to perform on small animals in poor health, such as, diabetes. The single bolus tracer-injection method for assessing GFR described in this report is: 1) independent of urine flow rate, 2) noninvasive (to the urinary tract), 3) requires no assumptions regarding the number of compartments in which the tracer is distributed or the general form of the plasma tracer activity curve, and 4) can be completed in less than 10 minutes following cannulation of vessels for injection of radiolabeled tracers and withdrawal of blood samples. Estimates of GFR obtained by this method agree closely with those obtained by conventional inulin clearance. The major limitation of the method is that it can be used only terminally, since the kidneys, ureters, and bladder are removed for quantification of tracer activity.