A comparison of two techniques for determining glomerular size distributions in domestic fowl.

Nephrons in the avian kidney have an extremely heterogeneous size distribution. The shortest nephrons have very small glomeruli, and the larger nephrons have very large glomeruli. Physiological, nutritional, and disease factors may be correlated with the functioning of different sized nephrons. The present study was conducted to compare two techniques for measuring glomerular size distributions. A postmortem India ink infusion technique gave results that were highly comparable to an in vivo alcian blue infusion technique. Single Comb White Leghorn pullets were found to have approximately 270,000 glomeruli per kidney; glomerular circumferences and diameters ranged between .07 to .42 mm and .02 to.14 mm, respectively. A unimodal size distribution was found, with most glomeruli falling within the circumference range of .15 to .26 mm. The alcian blue technique should provide a quantitative in vivo method for evaluating selective tubular damage or physiological glomerular intermittency.