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Anabolic effects of testosterone in bone of gonadectomized male and female rats
Author(s) -
Yarrow Joshua F,
Conover Christine F,
Conrad Bryan,
Zheng Niquan,
Wronski Thomas J,
Altman Molly K,
Franz Sarah E,
Borst Stephen E
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1188.5
Subject(s) - endocrinology , medicine , testosterone (patch) , anabolism , dihydrotestosterone , placebo , bone mineral , hormone , osteoporosis , androgen , alternative medicine , pathology
In males (M), testosterone (T) administration augments bone mineral density and maximal bone strength (MBS); however, the direct effects of T‐administration on female (F) bone are less understood. We evaluated the effects of supraphysiological T administration on M and F serum hormone concentrations [T, dihydrotestosterone (DHT), and estradiol (E2)], tibial cancellous bone volume % (CBV%), and femur MBS (3‐point bending test). Fisher SAS rats received Sham surgery + placebo (P), gonadectomy (GNX) + P, or GNX + T (7.0 mg x week‐1) for 28 days. GNX reduced serum T by 99%, DHT by 42–87%, and E2 by 72–82% in both sexes (p<0.05). When compared with Shams, T‐administration resulted in >18‐fold (M) and >100‐fold (F) increases in serum T, 17‐fold (M) and 50‐fold (F) increases in DHT, and a 4‐fold increase in E2 (M) concentrations (p<0.05); while reducing serum E2 by 55% in (F) (p<0.05). T‐administration also reversed the GNX induced reductions in CBV% in M (Sham 4.8±1.0, GNX 1.6±0.5, GNX+T 6.0±0.5; p<0.05) and resulted in a trend towards increased CBV% in F (Sham 9.8±5.7, GNX 3.5±2.6, GNX+T 7.4±3.5; p=0.052), when compared with GNX. Ultimately, GNX+T augmented MBS by ~6–12% in M and ~15–19% in F when compared with Sham and GNX, respectively (p<0.05). Our results indicate that supraphysiological T‐administration directly augments CBV% and MBS after GNX in both M and F rats. Study funded by VA Merit grant (S.E. Borst).