Resting energy expenditure, growth hormone indices, body composition and adipose tissue distribution in premenopausal women.

Abstract

OBJECTIVES: A significant growth hormone (GH) contribution to interindividual variance in energy expenditure (REE) in women can be hypothesized. The present study examines the independent association between physiological levels of GH function indices and REE. SETTING: All subjects were hospitalized in the Institute of Internal Medicine of the University of Verona. SUBJECTS: Twenty-four premenopausal overweight (BMI = 28-55 kg m-2) women aged 18-49 years. INTERVENTIONS: REE was estimated by indirect calorimetry and body composition and fat distribution by single slice computed tomography method. GH activity and GH status were determined by measuring serum levels of insulin-like growth factor I (IGF-I) and insulin-like growth factor binding protein-3 (IGFBP-3). RESULTS: GH indices did not show any significant correlation with REE. The relation between GH indices and REE was also examined by multiple regression analysis to account for possible confounders such as body composition, adipose tissue distribution and age. When body composition was considered, body fat and fat-free mass were the only significant predictors of REE (R2 = 0.699, P = 0.0001). The contributions of GH indices were not significant. CONCLUSIONS: Our findings do not support the hypothesis that GH in physiological conditions could be an independent determinant of REE in women with obesity.