Excessive Growth Hormone Expression in Male GH XXXX Adversely Alters Bone Architecture and Mechanical Strength.

@entity1 @entity2338 @entity10173 @entity174 @entity19 @entity2012 @entity79 @entity1053 @entity291
UNASSIGNED: @entity1 with @entity2012 have a higher prevalence of @entity174 despite normal @entity79 ( @entity79 ), suggesting that GH overexpression has adverse effects on skeletal architecture and strength. We used giant @entity291 GH (bGH) @entity19 to analyze the effects of high serum GH levels on @entity79 , architecture, and mechanical strength. Five-month-old hemizygous male bGH @entity19 were compared with age- and sex-matched nontransgenic littermates controls (NT; n=16/group). Bone architecture and @entity79 were analyzed in tibia and lumbar vertebrae using microcomputed tomography. Femora were tested to failure using three-point bending and bone cellular activity determined by bone histomorphometry. bGH @entity19 displayed significant @entity1053 and bone lengths. bGH tibia showed decreases in trabecular bone volume fraction, thickness, and number compared with NT ones, whereas trabecular pattern factor and structure model index were significantly increased, indicating deterioration in bone structure. Although cortical tissue perimeter was increased in @entity19 , cortical thickness was reduced. bGH @entity19 showed similar trabecular @entity79 but reduced trabecular thickness in lumbar vertebra relative to controls. @entity79 and thickness were significantly reduced in @entity2338 . Mechanical testing of femora confirmed that bGH femora have decreased intrinsic mechanical properties compared with NT ones. Bone turnover is increased in favor of bone resorption in bGH tibia and vertebra compared with controls, and serum @entity10173 levels is also enhanced in bGH @entity19 . These data collectively suggest that high serum GH levels negatively affect bone architecture and quality at multiple skeletal sites.
