Metabolic Effects of a Growth Hormone-Releasing Factor in Obese Subjects with Reduced Growth Hormone Secretion: A Randomized Controlled Trial

Abstract

Obesity is associated with reduced GH secretion and increased cardiovascular disease risk. We performed this study to determine the effects of augmenting endogenous GH secretion on body composition and cardiovascular disease risk indices in obese subjects with reduced GH secretion. A randomized, double-blind, placebo-controlled study was performed involving 60 abdominally obese subjects with reduced GH secretion. Subjects received tesamorelin, a GHRH(1-44) analog, 2 mg once daily, or placebo for 12 months. Abdominal visceral adipose tissue (VAT) was assessed by abdominal computed tomography scan, and carotid intima-media thickness (cIMT) was assessed by ultrasound. Treatment effect was determined by longitudinal linear mixed-effects modeling. VAT [-16 ± 9 vs.19 ± 9 cm(2), tesamorelin vs. placebo; treatment effect (95% confidence interval): -35 (-58, -12) cm(2); P = 0.003], cIMT (-0.03 ± 0.01 vs. 0.01 ± 0.01 mm; -0.04 (-0.07, -0.01) mm; P = 0.02), log C-reactive protein (-0.17 ± 0.04 vs. -0.03 ± 0.05 mg/liter; -0.15 (-0.30, -0.01) mg/liter, P = 0.04), and triglycerides (-26 ± 16 vs. 12 ± 8 mg/dl; -37 (-67, -7) mg/dl; P = 0.02) improved significantly in the tesamorelin group vs. placebo. No significant effects on abdominal sc adipose tissue (-6 ± 6 vs. 3 ± 11 cm(2); -10 (-32, +13) cm(2); P = 0.40) were seen. IGF-I increased (86 ± 21 vs. -6 ± 8 μg/liter; 92 (+52, +132) μg/liter; P < 0.0001). No changes in fasting, 2-h glucose, or glycated hemoglobin were seen. There were no serious adverse events or differences in adverse events between the groups. Among obese subjects with relative reductions in GH, tesamorelin selectively reduces VAT without significant effects on sc adipose tissue and improves triglycerides, C-reactive protein, and cIMT, without aggravating glucose.