The effect of lactation on the composition of long bones in rats

Abstract

Abstract Changes in the serum and the skeleton which occur during the lactation and postlactation period were studied in 60 control and 83 experimental female rats which were divided into 12 groups and killed at different intervals. A significant increase in calcium and citric acid and a decrease in phosphorus was observed in the blood serum during lactation. After weaning on the twenty-fifth day after delivery, the level of serum phosphonius increased very markedly, attaining much higher values than in the control group. In the skeleton, the percentage of dry weight and the content of bone mineral decreased. This absolute loss together with an increased amount of water content in the bone tissue indicated calcium and phosphorus mobilization. The significance of citric and pyruvic acids, regarding the metabolism of bone, has been briefly discussed.