title: Growth hormone mitigates loss of periosteal bone formation and muscle mass in disuse osteopenic rats.
abstract: Growth hormone (GH) is a potent anabolic agent capable of increasing both bone and muscle mass. The aim was to investigate whether GH could counteract disuse-induced loss of bone and muscle mass in a rat model. Paralysis was induced by injecting 4 IU Botox (BTX) into the muscles of the right hind limb. Sixty female Wistar rats, 14 weeks old, were divided into the following groups: baseline, controls, BTX, BTX+GH, and GH. GH was given at a dosage of 5 mg/kg/d for 4 weeks. Compared with controls, BTX resulted in lower periosteal bone formation rate (BFR/BS,-79%, P<0.001), bone mineral density (aBMD, -13%, P<0.001), trabecular bone volume (BV/TV, -26%, P<0.05), and mid-femoral bone strength (-12%, P<0.05). In addition, BTX reduced rectus femoris muscle mass (-69%, P<0.001) and muscle cell cross sectional area (CSA) (-73%, P<0.001) compared with controls. GH counteracted disuse-induced losses of periosteal BFR/BS (2-fold increase vs. BTX, P<0.001), whereas no effect on aBMD, trabecular BV/TV, or bone strength was found. In addition, GH partly prevented loss of muscle mass (+29% vs. BTX, P<0.001), and tended to prevent loss of muscle CSA (+11%, P=0.064). In conclusion, GH mitigates disuse-induced loss of periosteal BFR/BS at the mid-femur and rectus femoris muscle mass.
authors.affiliation: Department of Biomedicine, Aarhus University, Aarhus, Denmark.
authors.forename: M-C
authors.initials: MC
authors.lastname: Grubbe
authors.forename: J S
authors.initials: JS
authors.lastname: Thomsen
authors.forename: J R
authors.initials: JR
authors.lastname: Nyengaard
authors.forename: M
authors.initials: M
authors.lastname: Duruox
authors.forename: A
authors.initials: A
authors.lastname: Brüel
mesh_terms: D015502:Absorptiometry, Photon; D000818:Animals; D001851:Bone Diseases, Metabolic / Q000139:chemically induced; D001842:Bone and Bones / Q000187:drug effects*; D004195:Disease Models, Animal; D005260:Female; D013006:Growth Hormone / Q000494:pharmacology*; D018482:Muscle, Skeletal / Q000187:drug effects*; D020966:Muscular Disorders, Atrophic / Q000139:chemically induced; D009465:Neuromuscular Agents / Q000633:toxicity; D010012:Osteogenesis / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D013718:Tensile Strength / Q000187:drug effects; D055114:X-Ray Microtomography
chemical_list: D009465:Neuromuscular Agents; D013006:Growth Hormone