Diet-Induced Changes in the Exchange and Accretion of Radiostrontium by Rat Skeleton

Abstract

The administration of stable Ca or Sr to decrease the retention of radiostrontium by skeletal tissue has been employed by a number of investigators with equivocal results. The experiments were based chiefly on the carrier effect, the dilution of radiostrontiuru with stable Sr or Ca adruinistered just prior to or immediately after the adrninistration of the radiostrontium. A different approach was used to decrease the Sr/sup 85/ retention. This procedure is based on the hypothesis that a monolayer of Sr salts will be bound to the reactive sites of binding on the surface of the inoramic bone crystal with greater force than will a subsequent layer of Sr salts, since Ca phosphate is less soluble than Sr phosphate. Accordingly, stable Sr was administered in the diet for periods ranging from 2 to 7 days prior to the injection of Sr/sup 85/. Similar use of stable Ca and Zr was also investigated. It was found that there was a decrease of 76% in the retention of Sr/sup 85/ in young growing rats receiving a high-Sr diet for 7 days, as compared with animals fed a stock diet. The decreased uptake of Sr/sup 85/ was reflected in a decrease of both themore » Sr exchange capacity and the Sr accretion rate of the skeleton. A high-Ca diet also produced a decrease in the Sr/sup 85/, but much less than a Sr diet, and a Zr sulfate-supplemented stock diet was a little more effective than the high-Ca diet. (auth)« less