Comparative Renal Excretions of Glomerular Substances Following ‘Instantaneous’ Injection Into a Renal Artery

Abstract

The relative renal excretions of glomerular substances (substances such as creatinine, inulin and ferrocyanide that are neither reabsorbed, secreted, nor synthesized in the kidneys and are presumed to equilibrate across the glomerular capillary walls) were determined following nearly instantaneous injection into the renal artery of anaesthetized dogs. Urine collections are made from each ureter separately for 30 periods each of 30 seconds duration. To correct for recirculation, period by period subtraction is made of the amounts excreted by the control kidney from the amounts excreted by the kidney into which injection was made. Provided this correction is made, the period by period fractional excretions of glomerular substances tested in pairs are nearly identical as are the total renal extractions, in spite of the very rapid changes which occurred in the concentrations in blood.