Studies on the Relation between the Excretion of Sr and the Intake of Ca (Report 3)

Abstract

This study was projected for the purpose of knowing how to reduce the ⁹⁰Sr excretion from relation between amount of Ca and Mg intake.
Experimental: Twenty-four growing albino rats were subjected to this experiment, and they were divided into four groups. The Ist group was fed a low Ca-normal Mg diet and the 2nd a low Ca-high Mg diet and the 3rd high Ca-normal Mg diet and the 4th high Cahigh Mg diet.
The high Mg means to contain twice amount of Mg in the normal diet. Radioactive Sr (Sr-90) was injected into the abdominal cavity of the rat, 5μc per capita.
After the injection, urine and feces of the rats were collected every two days during the first 10 days, thereafter both were collected occasionally up to the thirtieth day.
Thirty days after the injection the rats were killed and under leg, incisor were taken off for determination of deposit activity in hard tissue.
Results: (1) The amount of ⁹⁰Sr excreted by the rats fed the high Ca diet was higher than that of the low Ca fed group. (2) In high Mg group, ⁹⁰Sr excretion in urine seemed to indicate higher trend than normal Mg fed group. (3) The retained amount of ⁹⁰Sr in hard tissue, especially, in the femur was larger in the low Ca group than that of the high Ca group. (4) In the report 2, the retained amount of ⁹⁰Sr in the teeth was larger than the under-leg. This different is presumable due to the duration to be anatomized. (5) The high amount of Mg uptake had no relation to depesiticn of ⁹⁰Sr, whereas it had in the case of high Ca uptake.