BACKGROUND: Endogenous and exogenous sex hormones affect changes in body composition during aging via independent and dependent effects on the growth hormone/insulin-like growth factor-1 (GH/ @entity442 ) @entity2270 and associated binding proteins (BP). METHODS: Fasting serum @entity442 , @entity2301 , @entity251 , @entity1815 , and sex hormone binding globulin were analyzed in 48 @entity1 on hormone replacement (HRT) (unopposed oral @entity172 , HRT+, 74.0 +/- 6 years), 135 @entity1 not on HRT (HRT-, 77.3 +/- 7 years), and 128 healthy @entity1 ( @entity1 , ). Total lean body mass (LBM) and total fat were measured by dual energy X-ray absorptiometry. RESULTS: Total LBM decreased with age in all groups (p = .05). LBM was greater, and @entity442 , @entity2301 , and @entity251 were lower in HRT+ versus HRT- @entity1 (p = .02, p = .01, p = .04, and, respectively). LBM in @entity1 was positively related to @entity442 (p = .02) and @entity251 (p < .01), whereas LBM was associated with @entity2301 (p = .04) and total fat (p < .001) in female HRT+ and total fat (p < .01) in HRT- @entity1 . @entity442 decreased with age in @entity1 and HRT- @entity1 (p < .01) but did not decrease in HRT+ @entity1 . Total fat significantly decreased across age (p < .05). Controlling for age and HRT, the rate of decrease in fat was slower in @entity1 versus @entity1 (p = .02). @entity2301 decreased in all groups across age (p < .01), and the ratio of @entity442 to @entity2301 decreased faster in @entity1 compared to HRT+ and HRT- @entity1 (p = .02). CONCLUSIONS: Our data indicate divergent influences of sex @entity230 , @entity442 , and @entity2301 on age-related changes in LBM in healthy elderly @entity1 and @entity1 .

Serum Sex Hormones, XXXX , and @entity2301 Exert a Sexually Dimorphic Effect on Lean Body Mass in Aging.

@entity1 :: ('9606', 'Species') :: ['women', 'men'] @entity172 :: ('MESH:D004967', 'Chemical') :: ['estrogen'] @entity251 :: ('MESH:D013739', 'Chemical') :: ['testosterone'] @entity230 :: ('MESH:D013256', 'Chemical') :: ['steroids'] @entity2301 :: ('3486', 'Gene') :: ['IGFBP3'] @entity442 :: ('3479', 'Gene') :: ['IGF-1'] @entity1815 :: ('MESH:D004970', 'Chemical') :: ['estrone'] @entity2270 :: ('MESH:C566610', 'Disease') :: ['axis']
@entity442 :: (3479,Gene) :: ['IGF-1']
