|Schroeder, E Todd|
Submitted to: Journal of Clinical Endocrinology and Metabolism
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/10/2009
Publication Date: 6/1/2009
Citation: Sattler, F.R., Castaneda-Sceppa, C., Binder, E.F., Schroeder, E., Wang, Y., Bhasin, S., Kawakubo, M., Stewart, Y., Yarasheski, K.E., Ulloor, J., Colletti, P., Roubenoff, R., Azen, S.P. 2009. Testosterone and growth hormone improve body composition and muscle performance in older men. Journal of Clinical Endocrinology and Metabolism. 94(6):1991-2001. Interpretive Summary: Changes in the secretion of several hormones with aging such as growth hormone and testosterone are associated with loss of muscle mass and function and accumulation of upper body fat. We examined the effects of supplementation with testosterone and growth hormone together on body composition and muscle performance in older men. One hundred twenty-two community-dwelling men were randomized to receive transdermal testosterone with or without growth hormone for 16 weeks. Testosterone produced significant gains in total lean mass, muscle strength, and aerobic endurance with significant reductions in whole-body and trunk fat mass. These effects appeared to be further enhanced with growth hormone supplementation.
Technical Abstract: CONTEXT: Impairments in the pituitary-gonadal axis with aging are associated with loss of muscle mass and function and accumulation of upper body fat. OBJECTIVES: We tested the hypothesis that physiological supplementation with testosterone and GH together improves body composition and muscle performance in older men. DESIGN, SETTING, AND PARTICIPANTS: One hundred twenty-two community-dwelling men 70.8 +/- 4.2 yr of age with body mass index of 27.4 +/- 3.4 kg/m2, testosterone of 550 ng/dl or less, and IGF-I in lower adult tertile (< or =167 ng/dl) were randomized to receive transdermal testosterone (5 or 10 g/d) during a Leydig cell clamp plus GH (0, 3, or 5 microg/kg . d) for 16 wk. MAIN OUTCOME MEASURES: Body composition by dual-energy x-ray absorptiometry, muscle performance, and safety tests were conducted. RESULTS: Total lean body mass increased (1.0 +/- 1.7 to 3.0 +/- 2.2 kg) as did appendicular lean tissue (0.4 +/- 1.4 to 1.5 +/- 1.3 kg), whereas total fat mass decreased by 0.4 +/- 0.9 to 2.3 +/- 1.7 kg as did trunk fat (0.5 +/- 0.9 to 1.5 +/- 1.0 kg) across the six treatment groups and by dose levels for each parameter (P < or = 0.0004 for linear trend). Composite maximum voluntary strength of upper and lower body muscles increased by 14 +/- 34 to 35 +/- 31% (P < 0.003 in the three highest dose groups) that correlated with changes in appendicular lean mass. Aerobic endurance increased in all six groups (average 96 +/- 137 sec longer). Systolic and diastolic blood pressure increased similarly in each group with mean increases of 12 +/- 14 and 8 +/- 8 mm Hg, respectively. Other predictable adverse events were modest and reversible. CONCLUSIONS: Supplemental testosterone produced significant gains in total and appendicular lean mass, muscle strength, and aerobic endurance with significant reductions in whole-body and trunk fat. Outcomes appeared to be further enhanced with GH supplementation.