Evaluation of an epinephrine test in obesity.

Abstract

In 38 healthy normal weight controland 106 obese subjects measurements were made of serum PBI, fasting plasma free fatty acid (FFA) level and level of FFA 30 minutes after injecting 0.5 mg. aqueous epinephrine subcutaneously. Serum PBI level did not significantly differ in the groups suggesting independence from body weight. Fasting FFA level increased with weight, a finding not exlained by this study. The rise in FFA following epinephrine decreased as body weight increased. The proportion of control and obese subjects with a rise in FFA less than 300–400 μEq./L. was the same. It has been claimed that a diminished or absent response of FFA to a fixed subcutaneous dose of epinephrine defines a category of “metabolic” obesity. On the basis of this study it would appear that decreased response in a similar number of control and obese indicates the variation inherent in a test of this kind rather than a metabolic defect. The diminished response with increasing weight appears to reflect the response of larger subjects to a fixed dose of epinephrine rather than impaired mobilization of FFA. In 38 healthy normal weight controland 106 obese subjects measurements were made of serum PBI, fasting plasma free fatty acid (FFA) level and level of FFA 30 minutes after injecting 0.5 mg. aqueous epinephrine subcutaneously. Serum PBI level did not significantly differ in the groups suggesting independence from body weight. Fasting FFA level increased with weight, a finding not exlained by this study. The rise in FFA following epinephrine decreased as body weight increased. The proportion of control and obese subjects with a rise in FFA less than 300–400 μEq./L. was the same. It has been claimed that a diminished or absent response of FFA to a fixed subcutaneous dose of epinephrine defines a category of “metabolic” obesity. On the basis of this study it would appear that decreased response in a similar number of control and obese indicates the variation inherent in a test of this kind rather than a metabolic defect. The diminished response with increasing weight appears to reflect the response of larger subjects to a fixed dose of epinephrine rather than impaired mobilization of FFA.