KINETICS OF STRONTIUM METABOLISM IN MAN

Strontium metabolism was studied in five adult males by external counts over various body locations, and serial samples of serum, urine, and stools for seven to fourteen days following parenteral administration of radioactive strontium (Sr85, physical half-life, sixty-five days), were collected. With the use of a d-c analogue computer, it was possible to simuulate the blooddisappearance and excretory-appearance curves with a four-compartmemit model and two bleed-outs, one representing loss of isotope from the exchangeable strontium space due to new-bone formation (accretion) and one representing excretion. The rates involved in this model suggested that the four compartmnent.s represemit serum, extravascular-extracellular fluid, intracellular fluid, and bone strontium. The latter represents about half the total exchangeable stromitiumn space. The model is presented as a possible poimit of departure for further investigatiomis of the many unkmiowmis which remain to be defined for a true represemitatiomi of the kinetics of strontium, calcium, or other bone-mimieral metabolism.