Blood perfusion Isolated rabbit kidney Functional state
Springer Online Journal Archives 1860-2000
Abstract. This report describes the technique and procedure for perfusing an isolated rabbit kidney with 25 ml heparinized autologous blood in a closed circuit including a pump and an oxygenator. The duration of the operative ischaemia was 5–8 min; the perfusion lasted 2.5 hours. An additional infusion was made to compensate for urinary losses. Renal blood flow increased progressively from 2.01±0.1 to 2.65±0.22* ml/g kidney weight (kw) per min (*P〈0.05). Between the first (P1) and the last (P4) urine collection period the glomerular filtration rate (GFR) fell from 288±25 to 217±38* µl/g kw per min, urine flow from 5.58±1.13 to 4.91±0.75 µl/g kw per min, Na+ excretion from 1.07±0.19 to 0.63±0.12* µmol/g kw per min, K+ excretion from 0.46±0.03 to 0.28±0.05* µmol/g kw per min, P excretion from 2.5±0.2 to 2.0±0.5 µg/g kw per min, Ca excretion from 0.4±0.1 to 0.12±0.05* µg/g kw per min, creatinine excretion from 6.94±0.32 to 5.68±0.54 µg/g kw per min, glucose excretion from 18.2±3.2 to 1.6±0.5* µg/g kw per min, the free water clearance (CH2O) from –6.57±0.85 to –5.10±1.31 µl/g kw per min and urine osmolality from 600±52 to 590±105 mOsm/kg, urea excretion from 0.75±0.16 to 0.95±0.13 µmol/g kw per min. Excretion of glucose, P or Ca was observed only above a given plasma threshold value, and no transport maximum was found for glucose or P. Ca reabsorption paralleled the Na reabsorption. The proximal tubule pressure, measured within the 1st h of perfusion, was 12.5±1.1 mm Hg. Histological examination at the end of the perfusion showed dilatation of the tubules as in the non-perfused kidneys, and the presence of numerous bacteria. Hypertonic urine (380–1110 mOsm/kg) was observed in the presence of vasopressin, in the latter's absence the urine was hypotonic urine (206–278 mOsm/kg). There was no correlation between renal plasma flow and the GFR. CH2O increased with increasing filtered Na+ load. In conclusion, the blood-perfused, isolated rabbit kidney has a fairly constant functional capacity for approximately 2 h.
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