THE EXCRETION OF URINE IN THE DOG

Abstract

Xylose was excreted by the normal dog kidney, at moderate to large urine flows, with a relatively high U/P ratio (3 experiments reported). Under phlorizin the glucose clearance rose to but never exceeded the xylose clearance, while the xylose clearance itself, or the xylose clearance relative to the urea clearance, remained unaffected (3 experiments reported). This indicates that there is no active reabsorption of xylose by the renal tubules. The pentose, xylose, the disaccharide, sucrose, and the trisaccharide, raffinose, all physiologically inert, were excreted (in simultaneous experiments [long dash]2 reported) in an identical quantitative manner relative to each passive reabsorption (by diffusion) from the concentrated urine in the tubules. For these and other reasons, it is believed that these sugars can be used to evaluate the quantity of glomerular filtrate with an error not exceeding a few per cent.