Volumetric Analysis of Glomerular Size in Kidneys of Mammals Living in Desert, Semidesert or Water-Rich Environment in the Sudan

Abstract

The glomerular volumes in the kidneys were studied in four species of mammals, including a desert rodent, the jerboa (Jaculus jaculus); the laboratory white rat (Rattus norvegicus); a semidesert-living subprimate, the "bush baby" (Galago senegalensis senegalensis); and a primate, the grivet monkey (Cercopitheus aethiops aethiops). The measurements of volume were made according to the method of Palkovits and Zolnai which gives quantitative statistical values for the relative volumes of the glomeruli. An exact relationship between the average of the glomerular volumes, kidney weight, and body weight was not found in these different mammals when compared to each other. If the average volumes of the cortical and of the juxtamedullary glomeruli are compared separately then it is seen that the desert-living animals have a much bigger difference in volume between the cortical and the juxtamedullary glomeruli than those animals which require free access to water. In the kidney of the desert rodent (jerboa) the difference in volume between the cortical and the juxtamedullary glomeruli is 101% and, in the semidesert-living "bush baby," 169%. On the other hand the corresponding difference of volume in the laboratory white rat is only 21% and in the grivet monkey 28%. Considering the great functional importance of the juxtamedullary glomeruli and deep nephrons of the kidney in relation to dehydration, the large size of these structures can be regarded as an adaptation to life in an arid environment.