TY - JOUR
T1 - Additive effect of voluntary exercise and growth hormone treatment on bone strength assessed at four different skeletal sites in an aged rat model
AU - Mosekilde, Li
AU - Thomsen, J. S.
AU - Orhii, P. B.
AU - McCarter, R. J.
AU - Mejia, W.
AU - Kalu, D. N.
N1 - Funding Information:
The authors are grateful for the excellent technical assistance of Birthe Gylling-Jørgensen, Department of Cell Biology, Institute of Anatomy, University of Aarhus, Aarhus, Denmark. Michael Hewitt is gratefully acknowledged for his help in revising the manuscript. This study was supported in part by NIH Grant AG13309 and by a University Grant program for osteoporosis from Proctor and Gamble Pharmaceuticals, Cincinnati, Ohio, and the Danish Medical Research Council (No. 9503020). The authors thank Genentech, South San Francisco, CA for providing the recombinant human growth hormone used in this study.
PY - 1999/2
Y1 - 1999/2
N2 - The aim of the study was to assess the effect of growth hormone (GH), voluntary exercise (Ex), and the combination of GH and Ex on bone strength, mass, and dimensions in aged, intact female rats. In addition, the effect of food restriction (FR) was studied. Fourteen-month-old virgin F-344 rats were divided into 6 groups with 13 animals in each: (1) baseline (BSL); (2) control + solvent vehicle (CTRL); (3) GH 2.5 mg/kg/day (GH); (4) exercise, voluntary: 0.6-0.7 km/day (Ex); (5) GH treatment and voluntary exercise (GH + Ex); and (6) FR. Group 1 was killed at the beginning of the study and served as baseline. All the other groups were killed after 18 weeks' treatment. The effects of aging and treatment regimes were measured at four different skeletal sites: lumbar vertebrae, femoral cortical bone, femoral neck, and the distal femoral metaphysis. Aging in itself induced a decline in vertebral body strength and ash density. At the appendicular skeletal sites, bone mass and strength were unchanged or increased. Treatment with GH alone induced a significant increase in the biomechanical parameters at the vertebral body and the femoral diaphysis, but not at the femoral neck or the distal femoral metaphysis. Voluntary exercise on its own increased load values significantly over CTRL at the vertebral body site, but not at any of the appendicular skeletal sites. The combination of GH and voluntary exercise resulted in an additive effect at the vertebral site and at the femoral diaphysis, and a synergistic (potentiating) effect at the two femoral metaphyses. FR, on the other hand, had a negative effect on cortical bone area and strength at the femoral diaphysis, but no significant effect on the other sites tested. We conclude that GH treatment and voluntary exercise both have skeletal anabolic effects; however, these effects are exerted to differing degrees at different sites. Importantly, when dosed together, GH and Ex have either an additive or synergistic anabolic effect on all sites (axial and appendicular). Copyright (C) 1999 Elsevier Science Inc.
AB - The aim of the study was to assess the effect of growth hormone (GH), voluntary exercise (Ex), and the combination of GH and Ex on bone strength, mass, and dimensions in aged, intact female rats. In addition, the effect of food restriction (FR) was studied. Fourteen-month-old virgin F-344 rats were divided into 6 groups with 13 animals in each: (1) baseline (BSL); (2) control + solvent vehicle (CTRL); (3) GH 2.5 mg/kg/day (GH); (4) exercise, voluntary: 0.6-0.7 km/day (Ex); (5) GH treatment and voluntary exercise (GH + Ex); and (6) FR. Group 1 was killed at the beginning of the study and served as baseline. All the other groups were killed after 18 weeks' treatment. The effects of aging and treatment regimes were measured at four different skeletal sites: lumbar vertebrae, femoral cortical bone, femoral neck, and the distal femoral metaphysis. Aging in itself induced a decline in vertebral body strength and ash density. At the appendicular skeletal sites, bone mass and strength were unchanged or increased. Treatment with GH alone induced a significant increase in the biomechanical parameters at the vertebral body and the femoral diaphysis, but not at the femoral neck or the distal femoral metaphysis. Voluntary exercise on its own increased load values significantly over CTRL at the vertebral body site, but not at any of the appendicular skeletal sites. The combination of GH and voluntary exercise resulted in an additive effect at the vertebral site and at the femoral diaphysis, and a synergistic (potentiating) effect at the two femoral metaphyses. FR, on the other hand, had a negative effect on cortical bone area and strength at the femoral diaphysis, but no significant effect on the other sites tested. We conclude that GH treatment and voluntary exercise both have skeletal anabolic effects; however, these effects are exerted to differing degrees at different sites. Importantly, when dosed together, GH and Ex have either an additive or synergistic anabolic effect on all sites (axial and appendicular). Copyright (C) 1999 Elsevier Science Inc.
KW - Aging
KW - Bone mass
KW - Bone strength
KW - Exercise
KW - GH treatment
KW - Rat model
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U2 - 10.1016/S8756-3282(98)00169-0
DO - 10.1016/S8756-3282(98)00169-0
M3 - Article
C2 - 9951773
AN - SCOPUS:0032929772
SN - 8756-3282
VL - 24
SP - 71
EP - 80
JO - Bone
JF - Bone
IS - 2
ER -