OBSERVATIONS ON THE CONCENTRATING AND DILUTING MECHANISMS OF THE DISEASED KIDNEY*

Abstract

One of 3 varieties of experimental renal disease was induced in a single kidney of dogs in which the opposite kidney is maintained intact as a control. The normal kidney serves to prevent the evolution of body fluid abnormalities seen in bilateral renal disease. In all the animals studied, regardless of the severity of the renal disease or the degree of anatomic disorganization, values for the concentrating and diluting capacities (expressed as ml of solute-free water abstracted or free-water cleared per 100 ml of glomerular filtrate) of the experimental kidneys were within the normal range. These data serve to document the essential integrity of the concentrating and diluting processes in the persisting nephrons of the diseased kidney, and strongly imply that the pathologic processes do not destroy specific functional sites in the tubule. A theoretical explanation is offered which allows for the decreasing range of urine osmolalities in bilateral renal disease despite intact concentrating and diluting processes.