Can albuterol help resistance exercise attenuate unloading-induced bone loss?
Hind-limb-suspended rats incur attenuated bone loss with beta(2)-agonists, and humans note similar changes with concurrent resistance exercise. To examine if the beta(2)-agonist albuterol helps resistance exercise reduce unloading-induced bone loss, human subjects performed 40 days of unilateral limb suspension with their left legs, otherwise refraining from normal ambulatory activity. While performing left leg strength training 3 days.week(-1), subjects received a concurrent placebo or albuterol (16 mg.day(-1)) treatment. Left leg muscle and bone changes were analyzed with 2 x 2 analyses of covariance (ANCOVAs). Mechanical loading values were calculated from workouts and compared using a 2 x 5 analysis of variance (ANOVA) and a Tukey post hoc test. The resistance exercise-albuterol assignment evoked significant (p < 0.05) left leg bone mineral content (BMC) gains (+2.24%) after 40 days. During the final unloading days, the resistance exercise-placebo group's mechanical loading data declined (-13.91%) significantly (p < 0.05) versus initial values. A resistance exercise-albuterol assignment likely increased BMC by maintaining the mechanical loading stimulus.
Caruso
John F
JF
Exercise Physiology Laboratory, University of Nevada, Reno, NV 89557, USA. john_caruso@utulsa.edu
Hamill
John L
JL
Yamauchi
Miki
M
Cook
Tim D
TD
Mercado
Dean R
DR
Gibb
Geoff
G
Higginson
Brian K
BK
Elias
Jeff
J
Hernandez
Dan A
DA
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000328:Adult; D000420:Albuterol / Q000494:pharmacology*; D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D015519:Bone Density / Q000187:drug effects* / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007103:Immobilization; D007866:Leg / Q000502:physiology*; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology; D010024:Osteoporosis / Q000517:prevention & control*
D000318:Adrenergic beta-Agonists; D000420:Albuterol