Administration of growth hormone in selectively protein-deprived rats decreases BMD and bone strength

Article Article scientifique Article Administration of growth hormone in selectively protein-deprived rats decreases BMD and bone strength eng 2010 author Ammann Patrick 24604 author Brennan Tara Clare 667794 author Mekraldi Samia 555503 author Aubert Michel 25310 author Rizzoli René 22717 1574-1581 10.1016/j.bone.2010.02.015 20178866 1873-2763 http://ac.els-cdn.com/S8756328210004370/1-s2.0-S8756328210004370-main.pdf?_tid=b48364f883ddfc7b90cda195b30e8757&acdnat=1335965034_fa6d29460b101bd0cc9ce1ab4f7457fa INTRODUCTION: Isocaloric protein undernutrition is associated with decreased bone mass and decreased bone strength, together with lower IGF-I levels. It remains unclear whether administration of growth hormone (GH) corrects these alterations in bone metabolism. MATERIALS AND METHODS: Six-month-old female rats were fed isocaloric diets containing either 2.5% or 15% casein for 2 weeks. Bovine growth hormone (bGH, 0.5 or 2.5mg/kg of body weight) or vehicle was then administered as subcutaneous injections, twice daily, to rats on either diet for 4 weeks. At the proximal tibia, analysis of bone mineral density (BMD), maximal load and histomorphometry were performed. In addition, urinary deoxypyridinoline, plasma osteocalcin and IGF-I concentrations were measured. Weight was monitored weekly. RESULTS: bGH caused a dose-dependent increase in plasma IGF-I regardless of the dietary protein content. However, bGH dose-dependently decreased BMD and bone strength in rats fed the low-protein diet. There was no significant effect of bGH on BMD in rats fed the normal protein diet within this short-term treatment period, however bone formation as detected by histomorphometry was improved in this group but not the low-protein group. Osteoclast surface was increased in the low-protein bGH-treated animals only. Changes in bone turnover markers were detectable under both normal and low-protein diets. CONCLUSION: These results emphasize the major importance of dietary protein intake in the bone response to short-term GH administration, and highlight the need for further investigation into the effects of GH treatment in patients with reduced protein intake. Animals Biomechanics/drug effects Body Weight Bone Density/*drug effects Bone and Bones/*drug effects/metabolism/*physiology Caseins Cattle Diet, Protein-Restricted/adverse effects Female Growth Hormone/*pharmacology Muscle, Skeletal/drug effects Rats Rats, Sprague-Dawley Dewey 610 Dewey 618 Dewey 618.97 Dewey 616 56 Département de médecine 221 58 Département de pédiatrie, gynécologie et obstétrique 223 65 Département de réadaptation et gériatrie 22B false 340 Etudes précliniques de l'ostéoporose 606 44 Nutrition et os 66 Bone 46 6 985841fa-bca8-4bc1-a4cc-3d9085a098e1 Article Restricted file1.pdf 1149772 application/pdf restrictedAccess Faculté de médecine / Section de médecine clinique / Département de médecine Faculté de médecine / Section de médecine clinique / Département de pédiatrie, gynécologie et obstétrique Faculté de médecine / Section de médecine clinique / Département de réadaptation et gériatrie

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Administration of growth hormone in selectively protein-deprived rats decreases BMD and bone strength	Bone			2010	632	0

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