Effects of Chronic Insufficiency of Drinking Water in White Mice

Previous dehydration studies have emphasized almost exclusively acute dehydration in white rats or larger laboratory mammals. There is little information on rodents smaller than rats, or on the effects of chronic dehydration on any sized mammal. In order to study dehydration uncomplicated by other changes, such as starvation, it may be necessary to cause water loss quickly— by forced diuresis (see Brokaw, 1949) or forced extrarenal loss by exposure to heat (Adolph, 1947). But, as pointed out by Brokaw, an animal's response to and toleration of a rapidly developing dehydration may be quite different from that of a slowly occurring water loss. There are fairly numerous reports of casual, limited observations of the general effects of water deficiency on small wild rodents (see review by Schmidt-Nielsen, 1952), but there have been few serious studies. The latter include studies of survival time on reduced water rations (Lindeborg, 1952), measurement of energy metabolism and water exchanges on extremely reduced water intakes (Chew, 1951), and measurement of water balance and kidney function in rodents on air-dry diets (Schmidt-Nielsen, 1952). Changes in the blood and in the water compartments of mice on restricted water intakes is an unexplored field.