title: Calcium tracer kinetics show decreased irreversible flow to bone in glucocorticoid treated patients.
abstract: Osteopenia resulting from pharmacologic doses of glucocorticoids is well known. Previously, there has been no satisfactory quantitative model describing the kinetics of calcium flow in subjects on chronic steroid use. A mathematical model of calcium isotope interaction with bone is described and applied to determine an estimate of kinetic parameters characterizing these changes. Calcium tracer dilution kinetics after a bolus injection of 42Ca were measured in 14 subjects with juvenile dermatomyositis, 6 on prednisone regimens and 8 on treatment regimens without prednisone. Irreversible tracer loss from plasma bone is found to be significantly reduced (P = 0.043) in the glucocorticoid-treated patients compared with patients on nonsteroid regimens. Reversible flow to bone is noted to be similar in the two groups. These results suggest a direct effect of glucocorticoids on osteoblast function.
authors.affiliation: Laboratory of Theoretical and Physical Biology, NICHD, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: R E
authors.initials: RE
authors.lastname: Goans
authors.forename: G H
authors.initials: GH
authors.lastname: Weiss
authors.forename: S A
authors.initials: SA
authors.lastname: Abrams
authors.forename: M D
authors.initials: MD
authors.lastname: Perez
authors.forename: A L
authors.initials: AL
authors.lastname: Yergey
mesh_terms: D000293:Adolescent; D001851:Bone Diseases, Metabolic / Q000139:chemically induced; D001842:Bone and Bones / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002127:Calcium Isotopes; D002648:Child; D003882:Dermatomyositis / Q000188:drug therapy / Q000503:physiopathology; D005260:Female; D005938:Glucocorticoids / Q000009:adverse effects*; D006801:Humans; D007201:Indicator Dilution Techniques; D008297:Male; D008954:Models, Biological; D010006:Osteoblasts / Q000187:drug effects
chemical_list: D002127:Calcium Isotopes; D005938:Glucocorticoids; D002118:Calcium