Oxandrolone, anabolism and women

Sheffield-Moore M, Paddon-Jones D, Casperson SL, Gilkison C, Volpi E, Wolf SE, Jiang J, Rosenblatt JI, Urban RJ. Androgen Therapy Induces Muscle Protein Anabolism in Older Women. J Clin Endocrinol Metab. 2006 Aug 8; [Epub ahead of print].

ABSTRACT

Context: Normal healthy men and women undergo a gradual loss of skeletal muscle mass and strength with advancing age. While androgens are protein anabolic in older men, the metabolic effects in older women are poorly understood. Objective and Design: The objective of this study was to determine whether oral administration of a synthetic derivative of Testosterone(oxandrolone, Oxandrin) (OX) (7.5 mg po bid for 14 days) to five older women (65 +/- 2 y) would enhance skeletal muscle anabolic biomarkers including mixed muscle fractional synthesis rate (FSR), net phenylalanine balance, androgen receptor (AR) and IGF-I protein expression at days 0, 5 and 14 of treatment. As a positive control, seven older men were examined following 14 days of OX (10 mg po bid). Setting: The study was performed at the General Clinical Research Center. Results: 14 days of OX significantly increased skeletal muscle FSR in older women (Day 0: 0.073 +/- 0.006 vs. Day 5: 0.092 +/- 0.006 vs. Day 14: 0.115 +/- 0.007%/h), (P < 0.05, Day 0 vs. Day 14). Conversely, OX stimulated FSR in older men after only 5 days (Day 0: 0.061 +/- 0.003 vs. Day 5: 0.101 +/- 0.01 vs. Day 14: 0.084 +/- 0.01%/h), (P < 0.05, Day 0 vs. Day 5). AR expression was significantly increased in older men by day 14, but had not increased in older women. No change was noted in IGF-I expression in either group. We conclude that the skeletal muscle of older women and men responds to androgen administration; though the time course of anabolism appears to be gender specific.