TY - JOUR
T1 - Analysis of the effects of growth hormone, exercise and food restriction on cancellous bone in different bone sites in middle-aged female rats
AU - Banu, Jameela
AU - Orhii, Paul B.
AU - Okafor, Maria C.
AU - Wang, Liping
AU - Kalu, Dike N.
N1 - Funding Information:
This study was supported in part by grants from the NIH (AG13309) and from the Texas Higher Education Coordinating Board. We thank Genentech (South San Francisco, CA) for providing us recombinant human growth hormone (rhGH).
PY - 2001
Y1 - 2001
N2 - The aim of this study is to determine the effects of growth hormone (GH), exercise (EX), GH + EX and food restriction on cancellous bone in middle-aged female rats. Female F344 rats aged 13 months were divided into (1) age-matched controls; (2) GH treated (2.5 mg/kg. 5 day/week); (3) EX (voluntary wheel running); (4) GH + EX; and (5) food restricted (FR) (fed 60% of the ad libitum food intake). The animals were treated for 18 weeks, at the end of which they were sacrificed. Cancellous bone and cortical bone in the fourth lumbar vertebra, proximal tibial metaphysis (PTM), distal femoral metaphysis (DFM) and femoral neck (NF) were analyzed using peripheral quantitative computerized tomography (pQCT) densitometry. Growth hormone increased cancellous bone area, cancellous bone mineral content, cortical bone area and cortical bone mineral content in the vertebra, PTM, DFM and NF. The tibial muscle wet weight was increased significantly after GH treatment. Exercise increased the cancellous bone area in the vertebra, PTM and DFM. Cortical bone area and cortical bone mineral content increased after EX in the vertebra, PTM, DFM and NF. No significant change was seen in the tibial muscle wet weight after EX. Growth hormone + EX increased cancellous bone area in the vertebra PTM and DFM but had no effect in neck of the femur. Cancellous bone mineral content, cortical bone area and cortical bone mineral content increased with GH + EX in the vertebra, PTM, DFM and NF. The tibial muscle wet weight was increased significantly with GH + EX. Food restriction decreased cancellous bone area and cancellous bone mineral content in all the bones studied. The decrease was statistically significant only at the distal femoral metaphysis. The tibial muscle wet weight decreased when compared with the age-matched control, but this decrease was not statistically significant. We conclude that the effect of the dose of GH used and the levels of voluntary wheel running EX used increased cancellous bone in intact rats; the effect of GH is much greater and different bones respond with varying intensities. The effects of combined treatment of GH and EX on cancellous bone are not always significantly higher than those of GH alone. FR at the level studied has a mostly negative effect on cancellous bone.
AB - The aim of this study is to determine the effects of growth hormone (GH), exercise (EX), GH + EX and food restriction on cancellous bone in middle-aged female rats. Female F344 rats aged 13 months were divided into (1) age-matched controls; (2) GH treated (2.5 mg/kg. 5 day/week); (3) EX (voluntary wheel running); (4) GH + EX; and (5) food restricted (FR) (fed 60% of the ad libitum food intake). The animals were treated for 18 weeks, at the end of which they were sacrificed. Cancellous bone and cortical bone in the fourth lumbar vertebra, proximal tibial metaphysis (PTM), distal femoral metaphysis (DFM) and femoral neck (NF) were analyzed using peripheral quantitative computerized tomography (pQCT) densitometry. Growth hormone increased cancellous bone area, cancellous bone mineral content, cortical bone area and cortical bone mineral content in the vertebra, PTM, DFM and NF. The tibial muscle wet weight was increased significantly after GH treatment. Exercise increased the cancellous bone area in the vertebra, PTM and DFM. Cortical bone area and cortical bone mineral content increased after EX in the vertebra, PTM, DFM and NF. No significant change was seen in the tibial muscle wet weight after EX. Growth hormone + EX increased cancellous bone area in the vertebra PTM and DFM but had no effect in neck of the femur. Cancellous bone mineral content, cortical bone area and cortical bone mineral content increased with GH + EX in the vertebra, PTM, DFM and NF. The tibial muscle wet weight was increased significantly with GH + EX. Food restriction decreased cancellous bone area and cancellous bone mineral content in all the bones studied. The decrease was statistically significant only at the distal femoral metaphysis. The tibial muscle wet weight decreased when compared with the age-matched control, but this decrease was not statistically significant. We conclude that the effect of the dose of GH used and the levels of voluntary wheel running EX used increased cancellous bone in intact rats; the effect of GH is much greater and different bones respond with varying intensities. The effects of combined treatment of GH and EX on cancellous bone are not always significantly higher than those of GH alone. FR at the level studied has a mostly negative effect on cancellous bone.
KW - Cancellous bone
KW - Exercise
KW - Food restriction
KW - Growth hormone
KW - Middle-aged female F344 rats
KW - pQCT
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U2 - 10.1016/S0047-6374(01)00243-3
DO - 10.1016/S0047-6374(01)00243-3
M3 - Article
C2 - 11337013
AN - SCOPUS:0035046987
VL - 122
SP - 849
EP - 864
JO - Mechanisms of Ageing and Development
JF - Mechanisms of Ageing and Development
SN - 0047-6374
IS - 8
ER -