Effect of saline adaptation and renal portal sodium infusion on glomerular size distributions and kidney function in domestic fowl.

Experiments were designed to evaluate acute and chronic effects of sodium on glomerular size distributions and kidney function of Single Comb White Leghorns. Chicks were raised on either tap water (control) or .6% NaCl (saline) drinking water. Kidney function studies were conducted when the birds reached 14 to 16 weeks of age. Saline-adapted birds had significantly lower glomerular filtration rates and significantly higher sodium and potassium excretion rates when compared with birds raised on tap water. Acute effects of sodium on kidney function were assessed by infusing 25 mM tetrasodium pyrophosphate unilaterally into the renal portal system. For birds raised on tap water, unilateral sodium infusion caused a significant unilateral reduction in the glomerular filtration rate. However, neither the acute nor the chronic reductions in glomerular filtration rates in response to sodium were associated with a reduction in the number of filtering nephrons. Saline-adapted birds had significantly hypertrophied glomeruli.