Biomedical Sciences ETDs

Publication Date



In order to study the effectiveness of body water and electrolyte regulation in young animals, the developmental pattern of renal function of rats in response to body fluid volume expansion with Ringer’s was investigated. Clearance experiments were performed on male Wistar rats of two age groups, twenty to thirty days and forty to sixty days of age. After two hours of a stabilization period, urine was collected for three consecutive twenty minute periods to establish a control value. The rats were then given an intravenous infusion of mammalian Ringer's solution of a volume equal to 4.6% o: body weight. Urine was collected for eighty minutes thereafter. The efficiency of the diuretic, natriuretic and kaliuretic responses were calculated. The diuretic efficiency was lower in the group between the ages of twenty and thirty days as compared to animals forty to sixty days of age. The twenty to thirty day old rats had a diuretic efficiency of 23. 8% while the older animals had a diuretic efficiency of 50. 2% (p<. 01) The natriuretic efficiency is also lower in the twenty to thirty day old group at 31.6% as compared to 56% for the forty to sixty day old animals, whereas the kaliuretic efficiency is not significantly different for the two groups. Also apparent are the continuous increase with age of both the blood pressure and the blood hematocrit. The response to a Ringer's infusion in both immature and mature animals may be a mixed response involving changes in physical factors and renal responses to volume expansion per sec. These results indicate that the response to Ringer's infusion is less efficient in rats twenty to thirty days of age than in adult rats and therefore suggest that the developmental pattern of the renal response to a Ringer's infusion is comparable to that seen in whole blood volume expansion over the range of ages of animals studied.

Document Type




Degree Name

Biomedical Sciences

Level of Degree


Department Name

Biomedical Sciences Graduate Program

First Committee Member (Chair)

Sidney Solomon

Second Committee Member

Albert Ratner

Third Committee Member

Kenneth George Kastella

Fourth Committee Member


Fifth Committee Member

William Raleigh Galey Jr.