Nonthyroidal control of metabolism after burn injury: Possible role of glucagon

The endocrine basis for control of metabolism in nonthyroidal illness is not yet understood. Burn injury is associated with reduced serum concentrations of thyroid hormones and with resting hypermetabolism. One index of severity is total burn size (TBS, % body surface). After overnight fasting and recumbency, resting metabolic rate (MR, O₂ consumption) was measured weekly and plasma was sampled for determination of glucose, total cholesterol, triglycerides, insulin, glucagon, somatostatin, growth hormone, norepinephrine, epinephrine, and cortisol in 28 burned men, 17-23 years old, TBS 2%-85%, including 8 controls with minimal injury (TBS ≤ 7.5%). MR was elevated in proportion to burn size mainly in the first week then declined toward normal. Growth hormone was not changed. Two multiple regression analyses (validated by random partitioning of data) determined which plasma variables independently reflected residual variation in MR: without TBS entered as a variable, high MR was associated with elevated glucose, cortisol, and glucagon, and low cholesterol (cumulative r² = 0.79); with TBS entered, high MR was associated with greater TBS, elevated norepinephrine, and again high glucagon and low cholesterol (r² = 0.81). Resting metabolism after burn injury is controlled not by the thyroid but may be controlled by a set of antiinsulin hormones that does not include growth hormone, but possibly includes glucagon.