Tracer Study on the Effect of Dietary Calcium Deficiency during Pregnancy in Rats

¹ Department of Physiology and the Radiation Research Laboratory, State University of Iowa, Iowa City, Iowa

Twenty-two female Holtzman rats were bred and divided into a control group and an experimental group. The control group was given a stock diet throughout pregnancy, while the experimental group was given a calcium-free diet. Both groups received a daily tracer dose of Ca-45 that was administered by stomach tube each morning. Immediately after delivery of the litter, the mother and the litter were sacrificed and subjected to analytical procedures to determine the per cent uptake of the orally administered Ca-45 which was to be found in the maternal femur and the litter, respectively. Also, maternal femur ash content and the ash content of the litter were determined and used as an index of calcium content in these structures.

From the data compiled, several facts could be noted: The per cent of orally administered Ca-45 that was retained by the calcium-stressed rats was 3.5-4.0 times the per cent retained by the control animals. There was no apparent redistribution of Ca-45 between the maternal femur and the litter of the experimental animals when compared with the control animals. There was no significant difference between the total litter ash in the experimental and control groups, but there was a highly significant difference between the femur ash content of the calcium-stressed animals and the femur ash content of the control animals.