THE EFFECT OF SIMPLE OBESITY ON GROWTH AND GROWTH-HORMONE

Simple obesity is characterized by a normal or increased growth rate w ith an acceleration of bone age maturation. When longitudinal growth s lows down in the presence of obesity, a hormonal disturbance should be sought. Despite normal growth, simple obesity is characterized by a r educed GH secretion evaluated by standard provocative tests, the admin istration of GH-releasing hormone or spontaneous 24-hour secretion. In obese children GH secretion may be as low as in poorly growing childr en with classical GH deficiency. The endocrine abnormalities along the GH axis seem to involve complex mechanisms at the hypothalamic, pitui tary and peripheral level. Recent data suggest that simple obesity is associated with an increase in GH clearance and a decrease in GH synth esis and secretion. It is also associated with high insulin and insuli n-like growth factor I levels which may interfere in the complex endoc rine interactions. In conclusion, simple obesity is characterized by n ormal growth in the presence of 'hyposomatotropism'.