The effects of recombinant human growth hormone (rhGH) supplementation on adipokines and C-reactive protein in obese subjects

ObjectiveObese subjects have functional growth hormone deficiency (GHD). Recombinant human GH (rhGH) treatment of pituitary GHD improves serum levels of leptin, adiponectin and C-reactive protein (CRP). This study was undertaken to determine whether these rhGH-induced changes occur in obese subjects during rhGH supplementation.DesignRandomized double-blind placebo-controlled trial of low-dose rhGH (200 μg/day for the first month, then 400 μg/day for men and 600 μg/day for women thereafter) or placebo supplementation as an adjuvant to a standard weight loss program.SubjectsForty healthy obese subjects, 28 premenopausal menstruating women (35 ± 7 SD years) and 12 men (37 ± 6 years).MeasurementsBody weight, BMI, body composition (assessed by dual energy X-ray absorptiometry [DEXA]), and serum levels of glucose, insulin, IGF-I, IGFBP-3, insulin resistance index (homeostasis modal assessment [HOMA]), leptin, CRP and adiponectin were performed at baseline and at 6 months.ResultsFor similar entry BMI values, women when compared with men had higher percent body fat (BF) (43.5 ± 4.6% vs. 29.8 ± 4.0%, p < 0.001), higher leptin levels (16.9 ± 8.4 μg/L vs. 4.2 ± 3.0 μg/L, p < 0.001), and higher CRP levels (13.8 ± 16.8 mg/L vs. 2.4 ± 3.2 mg/L, p = 0.04). Serum levels of leptin and CRP, but not adiponectin, correlated significantly with BF in both sexes. Recombinant human GH treatment increased levels of IGF-I Z-Score between baseline and 6 months (from −0.7 ± 0.9 SD to 0.1 ± 1.1 SD, p = 0.01) and modestly decreased BF (from 38.4 ± 7.8% to 35.6 ± 7.5%, p = 0.046). Despite increased IGF-I, there were no differences between rhGH and placebo with regard to changes in leptin, CRP, or adiponectin.ConclusionIt is concluded that in obesity, although rhGH treatment significantly increases IGF-I and modestly reduces body fat, the lack of significant changes in serum leptin, adiponectin or CRP levels suggests that rhGH treatment does not have a significant effect on these serum markers of adiposity.