The study of skeletal calcium metabolism with Ca-41 and Ca-45

Freeman, S.P.H.T. , Beck, B., Bierman, J.M., Caffee, M.W., Heaney, R.P., Holloway, L., Marcus, R., Southon, J.R. and Vogel, J.S. (2000) The study of skeletal calcium metabolism with Ca-41 and Ca-45. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 172, pp. 930-933. (doi: 10.1016/S0168-583X(00)00341-4)

Abstract

The living skeleton can be labeled for life by the administration of radiologically trivial amounts of Ca-41 tracer. After initial elimination of tracer from the readily exchangeable calcium pools subsequent skeletal calcium turnover maintains and modulates the urine Ca-41 content. Uniquely, bone calcium metabolism may then be studied with tracer in near equilibrium with the body's calcium and resorbing calcium directly measured by accelerator mass spectrometry (AMS) of excreta. Our experiments with 25 Ca-41 labeled subjects demonstrate excellent diurnal stability and remarkable response to intervention of the urine signal. Thus the tracer method may prove a competitive means of measuring the effects of antiresorptive osteoporosis treatments, for therapy development or even clinical monitoring. Novel studies of long-term skeletal evolution are also possible. We realize that routinely administered short-lived calcium radiotracers contain Ca-41 impurities and that thousands of experimental participants have been historically inadvertently Ca-41 labeled. The Ca-41 urine index might now rapidly further be characterized by contemporary measurements of these onetime subjects, and with their by now thoroughly skeleton-equilibrated tracer they might be ideal participants in other new experiments. We are also investigating Ca-45 AMS. It may prove preferable to label the skeleton with this radiotracer already familiar to bioscientists, but new to AMS.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Freeman, Professor Stewart
• Authors: Freeman, S.P.H.T., Beck, B., Bierman, J.M., Caffee, M.W., Heaney, R.P., Holloway, L., Marcus, R., Southon, J.R., and Vogel, J.S.
• Subjects: Q Science > QC Physics; Q Science > QD Chemistry; Q Science > QM Human anatomy
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
• ISSN: 0168-583X