Changes in insulin sensitivity induced by short-term growth hormone (GH) and insulin-like growth factor I (IGF-I) treatment in GH-deficient adults are not associated with changes in adiponectin levels

To test potential effects of altered insulin sensitivity on circulating adiponectin levels, we studied patients with GH deficiency (GHD) undergoing high dose GH and IGF-I treatment in a well-defined short-term setting. This design allowed to exclude confounding effects of GH and IGF-I treatment on body composition. Six patients (three women and three men) with acquired GHD were treated in a randomised cross-over trial with GH (subcutaneous injections of GH 0.03 IU/kg/daily) or IGF-I (continuous subcutaneous infusion of 5 μg/kg/h recombinant IGF-I) for 5 days. Median age of patients was 60 (range 25-72) years, BMI 24.7 (20.7-30.7) kg/m2, and baseline IGF-I concentration 60 (30-83) μg/L. HOMA scores (to assess insulin sensitivity) at baseline were 0.8 (0.3-11.7) and adiponectin concentrations were 7.0 (2.5-14.8) mg/L. HOMA scores increased rapidly and significantly up to a maximum of 2.7-fold (from baseline) at day 5 of GH treatment and returned promptly to baseline when GH was stopped, while adiponectin serum levels remained within the baseline range throughout the study period. HOMA scores dropped to a nadir of 0.66 from baseline at day 2 of IGF-I treatment whereas adiponectin levels remained within the baseline range. These data suggest that changes in insulin sensitivity (induced by high dose and short-term GH and IGF-I treatment) in patients with GHD are not associated with changes in adiponectin levels.