title: Effects of GH and/or sex steroid administration on abdominal subcutaneous and visceral fat in healthy aged women and men.
abstract: Aging is associated with reduced GH, IGF-I, and sex steroid axis activity and with increased abdominal fat. We employed a randomized, double-masked, placebo-controlled, noncross-over design to study the effects of 6 months of administration of GH alone (20 microg/kg BW), sex hormone alone (hormone replacement therapy in women, testosterone enanthate in men), or GH + sex hormone on total abdominal area, abdominal sc fat, and visceral fat in 110 healthy women (n = 46) and men (n = 64), 65-88 yr old (mean, 72 yr). GH administration increased IGF-I levels in women (P = 0.05) and men (P = 0.0001), with the increment in IGF-I levels being higher in men (P = 0.05). Sex steroid administration increased levels of estrogen and testosterone in women and men, respectively (P = 0.05). In women, neither GH, hormone replacement therapy, nor GH + hormone replacement therapy altered total abdominal area, sc fat, or visceral fat significantly. In contrast, in men, administration of GH and GH + testosterone enanthate decreased total abdominal area by 3.9% and 3.8%, respectively, within group and vs. placebo (P = 0.05). Within-group comparisons revealed that sc fat decreased by 10% (P = 0.01) after GH, and by 14% (P = 0.0005) after GH + testosterone enanthate. Compared with placebo, sc fat decreased by 14% (P = 0.05) after GH, by 7% (P = 0.05) after testosterone enanthate, and by 16% (P = 0.0005) after GH + testosterone enanthate. Compared with placebo, visceral fat did not decrease significantly after administration of GH, testosterone enanthate, or GH + testosterone enanthate. These data suggest that in healthy older individuals, GH and/or sex hormone administration elicits a sexually dimorphic response on sc abdominal fat. The generally proportionate reductions we observed in sc and visceral fat, after 6 months of GH administration in healthy aged men, contrast with the disproportionate reduction of visceral fat reported after a similar period of GH treatment of nonelderly GH deficient men and women. Whether longer term administration of GH or testosterone enanthate, alone or in combination, will reduce abdominal fat distribution-related cardiovascular risk in healthy older men remains to be elucidated.
authors.affiliation: Endocrine Section, Laboratory of Clinical Investigation, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, USA.
authors.forename: T
authors.initials: T
authors.lastname: Münzer
authors.forename: S M
authors.initials: SM
authors.lastname: Harman
authors.forename: P
authors.initials: P
authors.lastname: Hees
authors.forename: E
authors.initials: E
authors.lastname: Shapiro
authors.forename: C
authors.initials: C
authors.lastname: Christmas
authors.forename: M F
authors.initials: MF
authors.lastname: Bellantoni
authors.forename: T E
authors.initials: TE
authors.lastname: Stevens
authors.forename: K G
authors.initials: KG
authors.lastname: O'Connor
authors.forename: K M
authors.initials: KM
authors.lastname: Pabst
authors.forename: C
authors.initials: C
authors.lastname: St  Clair
authors.forename: J D
authors.initials: JD
authors.lastname: Sorkin
authors.forename: M R
authors.initials: MR
authors.lastname: Blackman
mesh_terms: D000005:Abdomen; D000273:Adipose Tissue / Q000033:anatomy & histology / Q000187:drug effects*; D000368:Aged; D015992:Body Mass Index; D001835:Body Weight; D004311:Double-Blind Method; D004958:Estradiol / Q000097:blood*; D015914:Estrogen Replacement Therapy; D005260:Female; D019382:Human Growth Hormone / Q000494:pharmacology*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008279:Magnetic Resonance Imaging; D008297:Male; D010919:Placebos; D012016:Reference Values; D012727:Sex Characteristics; D013739:Testosterone / Q000031:analogs & derivatives / Q000097:blood* / Q000494:pharmacology*; D014481:United States; D014781:Viscera; D044465:White People
chemical_list: D010919:Placebos; D019382:Human Growth Hormone; D013739:Testosterone; D004958:Estradiol; D007334:Insulin-Like Growth Factor I; C004648:testosterone enanthate