This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Fritz, P. C. Articles by Tenenbaum, H. C. Search for Related Content PubMed PubMed Citation Articles by Fritz, P. C. Articles by Tenenbaum, H. C.

Tamoxifen Attenuates the Effects of Exogenous Glucocorticoid on Bone Formation and Growth in Piglets¹

Medical Research Council Group in Periodontal Physiology, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada M5G 1G6; and the Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada L8N 3Z5

Address all correspondence and requests for reprints to: Dr. H. C. Tenenbaum, Faculty of Dentistry, University of Toronto, 124 Edward Street, Toronto, Ontario, Canada M5G 1G6. E-mail: htenenbaum{at}dental.utoronto.ca

Tamoxifen (Tam) has been shown to inhibit dexamethasone (Dex)-mediated effects on bone formation in vitro. Our objective was to determine whether Tam would block Dex-induced osteopenia and growth inhibition in growing piglets. Four-day-old male Yorkshire piglets were adapted to a liquid formula diet (400 ml/kg·day) and randomized to one of four groups (n = 5/group): Dex (0.5 mg/kg·day), Tam (1 mg/kg·day), Dex plus Tam, or placebo control (vehicle only). Both drugs were administered by orogastric gavage twice daily for 12 days. At baseline and at the end of treatment, whole body bone mineral density (BMD) was determined by dual energy x-ray absorptiometry (Hologic QDR1000W). Plasma osteocalcin and PTH were measured on days 0 and 12, and urinary N-telopeptide was measured on day 12. Changes in axial length and daily weight were also measured. Delta whole body BMD was 29% lower (P < 0.05) in Dex alone treated piglets than in controls (0.033 vs. 0.047 g/cm², respectively), whereas the maximum change in BMD in Dex plus Tam group (0.046 g/cm²) was similar to that in controls. Concurrent Tam administration reduced the Dex-induced deficit in weight gain by 56% (P < 0.05) and the deficit in axial length gain by 72% (P < 0.01). In Dex alone treated piglets, PTH was significantly elevated (7-fold), whereas osteocalcin and N-telopeptide were significantly reduced compared with control values. These effects were prevented by Tam. These data suggest that the suppression of growth and other changes in parameters of bone metabolism induced by glucocorticoids in vivo can be attenuated by Tam.