Measurement of the flux of lead from bone to blood in a nonhuman primate (Macaca fascicularis) by sequential administration of stable lead isotopes.

To better understand the kinetics of the transfer of lead from bone to blood, we have developed and tested a method in which sequential doses of lead, each enriched with a different stable isotope, were administered in a nonhuman primate Macaca fascicularis whose skeleton had been previously labeled with lead of known isotopic composition. Lead isotopic ratios of blood and bone samples, analyzed by thermal ionization mass spectrometry (TIMS), were unmixed by isotope dilution techniques. The first label administered allows the contribution from historical bone stores to be measured. Subsequent labels allow measurement of both the historical bone stores and the previous labels that have become recently incorporated into bone. The method may be extended to studies of bone lead mobilization in pregnancy, lactation, menopause, or in disease states such as postmenopausal osteoporosis.