Age-dependent polydipsia in the SWR/J mouse

Abstract

Both absolute water intakes (ml) and relative water intakes (ml/100 g body weight) increased with age in the SWR/J mouse. This age-dependent polydipsia was more pronounced in the females than in the males. The polydipsia was abolished by food deprivation and by giving a 20% sucrose solution in place of water. Intakes of polydipsic mice were elevated still further by offering 5% sucrose and 0.2% and 0.5% saccharin. The well-defined circadian rhythm of drinking in this strain was not altered by the development of polydipsia. In females, the increase in water intakes was accompanied by a decrease in intakes of isotonic and hypertonic NaCl solutions in a single tube test. It is suggested that the SWR/J mouse might provide a model for the study of behavioral changes accompanying age-dependent renal deterioration.