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

OBJECTIVE: Obese 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.

DESIGN: Randomized double-blind placebo-controlled trial of low-dose rhGH (200 microg/day for the first month, then 400 microg/day for men and 600 microg/day for women thereafter) or placebo supplementation as an adjuvant to a standard weight loss program.

SUBJECTS: Forty healthy obese subjects, 28 premenopausal menstruating women (35+/-7 SD years) and 12 men (37+/-6 years).

MEASUREMENTS: Body 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.

RESULTS: For 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 microg/L vs. 4.2+/-3.0 microg/L, p<0.001), and higher CRP levels (13.8+/-16.8 mg/L vs. 2.4+/-3.2mg/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.

CONCLUSION: It 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.