Influence of obesity and body fat distribution on growth hormone kinetics in humans

We studied the kinetics of exogenous recombinant 22-kDa human growth hormon e (rhGH) in premenopausal women with upper body obesity (UBO), lower body o besity (LBO), or normal body weight. A bolus of 100 mU rhGH was administere d during a continuous infusion of somatostatin to suppress endogenous GH se cretion. GH kinetics were investigated with noncompartmental analysis of pl asma GH curves. GH peak values in response to GH infusion and plasma half-l ife of GH were not significantly different between normal weight and obese subjects. In contrast, GH clearance was 33% higher in LBO women and 51% hig her in UBO women compared with clearance in normal weight controls. The dif ference in clearance between LBO and UBO was not statistically significant. Altered GH clearance characteristics contribute to low circulating GH leve ls in obese humans. Body fat distribution does not appear to affect GH kine tics.