85Sr Retention in Japanese after a Single Administration

The retention of 85Sr administered intraveneously or orally to 14 Japanese was studied for the period of less than one month. The whole body retention curve, as determined from excreta, could be fitted well by a sum of two component exponential functions when the amount of 85Sr exogenously excreted into the feces was excluded. However, the sizes and the rate constants of the respective components varied with individuals. The absorption coefficient of 8oSr was calculated for four subjects and found to be about 50 percent for normal cases and 30 percent for subjects with osteoporosis. Cumulative urinary excretion of 85Sr was not less than cumulative fecal excretion for absorbed 85Sr. The fractions (fu) of the element excreted in 24 hr- urine over that in 24 hr- total excreta of both stable Sr and Ca, which included exogenous origins, were higher for the subjects in this study than those to be reported for the normal male adults. The fraction varied greatly day to day when the amount of stable Sr exogenously excreted into the feces was included in this calculation. Higher content of stable Sr in the excreta of the subjects in this study was generally observed in comparison with those of the normal male adults, but the amount of Ca in excreta of the subjects in this study was comparable to that of the normal male adults. © 1973 Oxford University Press. All rights reserved.