Serum growth hormone and energy supply in fasting obese patients

Serum growth hormone (GH) levels, plasma free fatty acids (FFA) and blood glucose were determined during periods of total starvation in 13 severely obese patients, 2 of whom were suffering from hypopituitarism, and in 2 normal volunteers. In all individuals nitrogen excretion was measured and the total caloric expenditure calculated. The percentile contribution of protein to total caloric expenditure (protein RATIO = PR) appeared to be lower in the obese than in the normals. GH-values rose steeply in the normals on starvation. In the serum of 4 of the obese no GH could be found, the others showed a slight to moderate response. When these 2 groups of obese were compared with regard to nitrogen excretion, caloric expenditure and PR, no difference was found. Both hypopituitary patients were treated with a small maintenance dose of cortisone. They tolerated starvation well. Their caloric expenditure was lower, but their nitrogen excretion as well as PR-values were in the same range as those of the other obese. From these findings it is concluded that in the obese patients studied, fat mobilization was certainly not impaired but rather more easily accomplished than in the normals. It appeared not to be dependent on demonstrable levels of serum-GH and is probably also independent from other anterior pituitary factors. Plasma-FFA rose less in the obese than in the normals. A slight correlation between GH and FFA but no correlation between blood sugar and GH was found on simultaneous determinations