Kidney function in domestic fowl with chronic occlusion of the ureter and caudal renal vein.

A previously published technique for producing renal insufficiency in chicks involves ligating the caudal renal vein together with the ureter near the midpoint of the kidney. This ligation occludes the normal route (caudal renal vein) by which blood exits the medial and posterior kidney divisions. The present study was conducted to evaluate kidney function following chronic caudal renal vein and ureter occlusion. The ureters and caudal renal veins of 2 to 3-week-old chicks were clamped with hemostatic clips (Clamp Group), and kidney function evaluations were conducted when the birds reached 14 weeks of age. Plasma values [osmolality, Na, K, Ca, inorganic P (Pi)] of control, sham, and clamp groups did not differ significantly. Plasma uric acid concentrations did not differ when the control and clamp groups were compared. Clamping the ureter near the midpoint of the kidney caused a significant reduction in the number of filtering glomeruli per kidney, but due to compensatory hypertrophy the kidney weights of the groups did not differ significantly. Kidney function comparisons (urine flow rates, glomerular filtration rates, renal plasma flow rates, urine pH, fractional excretion of Na, K, Ca, Pi, and uric acid) revealed a significant reduction in Na and K excretion by the clamp group, but other renal function parameters did not differ significantly. These experiments demonstrate that chickens have a remarkable capacity to survive significant reductions in renal mass and to adapt to major disruptions of blood flow patterns.